CULAR 
MECHANISM  OF  THE  EYES 


AND 


ROUTINE  IN  EYE  WORK 


SAVAGE 


/     BERKELEY 

RY 

I   Of 


THE  NERVO-MUSCULAR 
MECHANISM  OF  THE  EYES 


AND 


ROUTINE  IN  EYE  WORK 


BY 

G.  C.  SAVAGE,  M.D. 


Author  of  New  Truths  in  Ophthalmology   (1S93);   of  Ophthal 

mic    Myology     (1902-11);     of    Ophthalmic    Neuro-Myology 

(1905);    Ex-President    of    the    Nashville    Academy    of 

Medicine;    Ex-President    of    the    Tennessee    State 

Medical     Association;      Ex-President     of     the 

Southern   Medical   Association;    Ex-Chah- 

man   of  Section   of   Ophthalmology   of 

American   Medical   Association. 


Three   full-page   plates   and   four   cuts 


Published  by  the  Author,   Nashville,   Tenn. 
Printed  by  McQuiddy  Printing  Company,   Nashville,   Tenn. 


OPTOMETRY  LIBRARY 


Copyright,   1916 
By  G.   C.   Savage.   M.D. 


PREFACE 

This  little  book  is  published  with  the  hope  that 
its  contents  will  create,  in  the  minds  of  many 
readers,  a  desire  to  take  up,  with  the  view  of 
mastering,  the  whole  study  of  the  ocular  mus- 
cles ;  also  with  the  view  of  intensifying,  in  other 
readers,  such  a  desire  as  may  have  been  pre- 
viously created,  but  allowed  to  remain  unsatis- 
fied, because,  forsooth,  some  one,  supposed  to  be 
a  leader  in  everything  worth  while,  had  said  that 
"  the  muscle  study  is  a  myth,  or  at  most  is  not 
worth  serious  consideration."  In  all  the  domain 
of  Ophthalmology  there  is  no  other  subject  of 
equal  importance  with  that  of  Ophthalmic  My- 
ology, and  yet  it  is  a  study  easily  mastered,  when 
mastery  is  earnestly  sought,  both  from  the  sci- 
entific viewpoint  and  that  of  practicality.  Any 
neglect  of  this  study  is  hurtful  to  the  patient  and 
harmful  to  the  practitioner.  In  his  books  and 
papers  the  aim  of  the  author  has  always  been  to 
make  clear  and  easy  the  study  of  the  ocular  mus- 
cles from  the  only  two  points  of  view — the  mus- 
cles themselves  and  the  brain  centers  controlling 
them  in  their  individual  and  associated  actions. 


BERKELEY 

RY 

UNIVERSITY  OP 

CALIFORNIA 


THE   NERVO-MUSCULAR   MECHAN- 
ISM OF  THE  EYES* 

In  the  study  of  the  motility  of  the  eyes, 
there  are  fundamentals  that  must  be 
known  and  appreciated  in  order  that  the 
subject  may  be  clearly  understood.  These 
fundamentals  may  be  briefly  stated  as  fol- 
lows : 

1.  The  image  of  the  object  on  which 
the  'vision  is  to  be  fixed  must  lie  on  the 
macula. 

2.  The  lines  connecting  this  image  and 
its  object  must  be  straight  lines  passing 
through  the  center  of  the  retinal  concave. 

3.  Every  other  object  in  the  visual  field 
and  its  image  must,  likewise,  be  connected 
by  straight  lines  passing  through  the  center  of 
the  retinal  concave. 

4.  All  visual  lines,  whether  direct  or  in- 
direct, are  radii  of  the  retinal  curvature 
prolonged,  and  hence  each  visual  line  must 
cross  all  other  visual  lines  at  the  center  of 
the  retinal  concave. 

5.  Any  two  objects  in  viewable  space 
bear  the  same  relationship,  in  degrees, 
as  do  their  retinal  images. 

6.  The  direct  or  primary  line  of  vision 


•Read  in  Eye,  Ear,  Nose  and  Throat  Section.  Southern 
Medical  Association,  Ninth  Annual  Meeting.  Dallas.  Tex., 
Nov.  8-11,  1915.  Reprint  from  the  Southern  Medical  Jour- 
nal,  Birmingham,   Ala. 


6      The  Nervo-Muscular  Mechanism  of  the  Eyes 

is  the  visual  axis  which  starts  from  the 
central  point  of  the  macula,  while  all  other 
visual  lines  are  indirect  or  secondary. 

7.  Any  secondary  point  in  space  may 
become  the  point  of  direct  view  by  a  shift- 
ing of  the  visual  axis  into  the  position  of 
the  secondary  visual  line  which  connected 
that  point  with  its  image  before  the  rota- 
tion began,  which  is  possible  only  because 
the  rotation  is  around  that  point  through 
which  all  visual  lines  pass,  the  center  of 
the  retinal  concave,  which  is  the  center  of 
rotation. 

Only  on  the  conceptions  stated  above 
can  be  formulated  the  true  mental  law  of 
visible  direction :  "All  lines  of  direction 
are  radii  of  retinal  curvature  prolonged.'' 
In  the  light  of  this  law  all  ocular  ro- 
tations can  be  understood;  but,  before 
studying  these  rotations  and  the  means  by 
which  they  are  accomplished,  some  essen- 
tial physical  properties  of  the  globe  must 
be  set  forth.  The  poles  of  the  eye  must  be 
correctly  located ;  the  -meridians  must  be 
properly  constructed;  and  the  equator 
must  be  fitly  related  to  the  poles.  The 
fatal  mistake  of  Helmholtz,  in  his  chapter 
on  "Movements  of  the  Eyes,"  was  in  his 
not  making  the  central  point  of  the  macula 
always  the  posterior  pole  of  the  eye.  He 
fell  into  this  error  because  he  chose,  as 
the  location  of  the  anterior  pole  of  the 


The  Nervo-Muscular  Mechanism  of  the  Eyes     7 

eye,  the  center  of  the  corneal  curve.  His 
optic  axis  he  constructed  by  carrying  a 
line  from  his  supposed  anterior  pole  back 
through  the  center  of  rotation  to  the  ret- 
ina, and  named  the  retinal  end  of  that 
line  the  posterior  pole.  Confessing,  as  he 
did,  that  in  ideal  eyes  the  posterior  pole 
and  the  central  point  of  the  macula  were 
one  and  the  same,  he  gave  himself  the 
opportunity  to  rid  himself  of  his  error  in 
locating  the  poles.  That  he  did  not  do 
this  is  explainable  only  on  the  ground  of 
his  false  conception  of  the  law  of  visible 
direction  which  may  be  expressed  in  these 
words:  "All  lines  of  direction  are  axial 
rays  of  light  and  cross  each  other  at  the 
nodal  point."  His  conception  of  the  law 
of  visible  direction  and  his  location  of  the 
poles  of  the  eye  made  his  location  of  the 
equator  incorrect  and  his  construction  of 
the  corneo-retinal  meridians  wrong. 

With  the  center  of  the  macula  as  the 
posterior  pole  of  all  eyes,  the  anterior  pole 
may,  or  may  not,  be  the  center  of  the  cor- 
nea. .  It  is  the  center  of  the  cornea  only 
in  ideal  eyes.  Through  the  true  posterior 
pole  of  the  eye  all  retinal  meridians  pass. 
Therefore,  the  center  of  the  macula  is 
common  to  all  the  retinal  meridians.  The 
only  other  point  through  which  these  me- 
ridians can  pass  is  the  anterior  pole,— -the 
second  common  point  for  all    meridians. 


8     The  Nervo-Muscular  Mechanism  of  the  lives 

The  only  line  common  to  the  planes  of  all 
the  meridians  is  the  line  connecting  the 
two  poles,  the  visual  axis  which,  in  all 
eyes,  is  the  true  optic  axis. 

The  equator  of  the  eye  is  that  circle 
which  passes  around  the  eye,  equally  dis- 
tant, everywhere,  from  the  two  poles.  Its 
plane  cuts  the  center  of  rotation  and  is  at 
right  angles  to  the  planes  of  all  the  me- 
ridians. In  the  plane  of  the  equator  there 
lie  as  many  diameters  as  there  are  me- 
ridional planes;  but  only  two  of  these  de- 
mand any  study.  These  two  diameters  lie, 
respectively,  in  the  planes  of  the  vertical 
and  horizontal  meridians,  as  well  as  in 
the  plane  of  the  equator.  It  is  around 
one  or  both  of  these  diameters,  as  axes, 
that  all  possible  ocular  rotations  must 
take  place.  The  line  to  be  guided  by  the 
muscles  and  nerves  of  the  eye,  in  any  ro- 
tation, is  common  to  the  planes  of  both 
the  vertical  and  horizontal  meridians, 
which  has  already  been  shown  to  be  the 
visual  axis, — the  true  optic  axis, — around 
which  rotations  are  denied,  except  in  nat- 
ural or  artificial  oblique  astigmatism. 

In  space,  just  as  in  the  eye,  there  are 
points  and  lines,  both  straight  and  curved, 
to  be  known  in  order  to  arrive  at  a  cor- 
rect understanding  of  ocular  rotations. 
One  of  these  lines  is  the  visual  axis  ex- 
tended, on  which  must  lie  any  object  to  be 


The  Nervo-Muscular  Mechanism  of  the  Eyes     9 

looked  at  fixedly.  The  location  of  such  an 
object  or  point  is  the  spacial  pole  of  the 
eye.  While  the  anterior  and  posterior 
poles  of  the  eye  have  a  fixed  distance  be- 
tween them  and  can  not  vary  their  dis- 
tance from  the  center  of  rotation,  the  spa- 
cial pole  may  be  at  any  distance  from  the 
two  ocular  poles  and  from  the  center  of 
rotation.  Through  the  spacial  pole  of  an 
eye  pass  spacial  meridians,  which  are 
great  circles  concentric  with  the  retinal 
meridians.  The  planes  of  the  vertical  and 
horizontal  retinal  meridians  prolonged 
into  space  become  the  planes  of  the  verti- 
cal and  horizontal  spacial  meridians.  The 
planes  of  all  oblique  retinal  meridians  bear 
a  like  relationship  to  the  oblique  spacial 
meridians.  No  point  can  be  in  viewable 
space  which  does  not  lie  on  some  spacial 
meridian,  and  the  eye  is  so  constructed, 
as  to  its  refractive  power,  as  to  compel 
the  image  of  that  point  to  fall  on  the  reti- 
nal meridian  having  a  common  plane  with 
the  spacial  meridian.  Such  a  point  in 
space,  if  secondary,  is  just  as  far  removed, 
in  degrees,  from  the  spacial  pole  as  its 
image  is  removed  from  the  central  point 
•  of  the  macula.  The  line  connecting  the 
secondary  point  and  its  image  forms  its 
two  angles  with  the  visual  axis  at  the  cen- 
ter of  rotation,  which  angles  are  equal  be- 
cause opposite. 


10    The  Ncn'o-Muscular  Mechanism  of  the  Eyes 

The  spacial  equator  is  in  the  plane  of 
the  equator  of  the  eye,  but  the  former  va- 
ries in  size,  always  corresponding  with 
the  spacial  meridians  both  as  to  size  and 
as  to  its  distance  from  the  center  of  rota- 
tion. Any  number  of  small  spacial  cir- 
cles may  be  constructed  parallel  with  the 
spacial  equator  and  between  it  and  the 
spacial  pole,  their  diameters  growing 
shorter  and  shorter  as  they  proceed  from 
the  equator  toward  the  pole,  reaching  zero 
at  the  pole.  For  convenience  of  study, 
these  spacial  parallels  may  be  placed  10° 
apart,  the  point  of  starting  being  the  spa- 
cial pole.  Likewise  retinal  parallels  might 
be  constructed  10°  apart,  the  smaller  one 
being  10°  from  the  posterior  pole  of  the 
eye.  Since  the  spacial  meridians  corre- 
spond with  their  respective  retinal  me- 
ridians, point  with  point  everywhere,  a 
spacial  parallel  at  a  given  distance  from 
the  spacial  pole  must  correspond  every- 
where with  a  retinal  parallel  located  the 
same  number  of  degrees  from  the  poste- 
rior pole  of  the  eye. 

With  the  foregoing  facts  fixed  in  the, 
mind,  ,  monocular  rotations  ought  not  to 
be  difficult  to  understand.  In  monocular 
rotation  every  rotation  plane  is  a  merid- 
ional plane  extended,  and  in  the  spacial 
part  of  this  plane  lie  both  the  first  and 
second  points  of  view,  while,  in  its  retinal 


The  Nervo-Muscular  Mechanism  of  the  Eyes    11 

part,  lie  the  images  of  the  two  points. 
The  first  point  of  view  must  be  at  the 
spacial  pole  and  its  image  must  be  on  the 
central  point  of  the  macula;  the  second 
point  of  view  must  be  just  as  many  de- 
grees from  the  spacial  pole,  on  a  given 
spacial  meridian,  as  its  image  is  removed 
from  the  retinal  pole,  on  the  correspond- 
ing retinal  meridian.  The  change  from 
the  one  point  of  view  to  the  other  is  but 
a  shifting  of  the  visual  axis  in  the  plane 
common  to  the  following  five  points:  the 
first  and  second  points  of  view,  their  two 
retinal  images,  and  the  center  of  rotation. 
In  the  shifting  the  spacial  end  of  the  vis- 
ual axis  moves  from  the  primary  to  the 
secondary  point,  while  the  retinal  end 
moves  from  the  primary  to  the  secondary 
image,  the  motion  being  around  the  cen- 
tral point  of  the  retinal  concave,  which 
is  also  the  central  point  of  the  spacial  con- 
cave. 

Every  pair  of  eyes,  endowed  with  the 
possibility  of  binocular  single  vision,  can 
be  made  to  fuse  their  respective  spacial 
fields  into  a  single  binocular  spacial  field, 
with  a  binocular  pole,  meridians  and  par- 
allels. The  fundamental  fact  of  binocu- 
lar single  vision  is  common  brain  cell  con- 
nection; that  is,  each  visual  cell  is  diax- 
onic,  one  axone  going  to  a  point  in  one 
retina,while  the  other   axone   goes   to   a 


12    The  Nervo-Muscular  Mechanism  of  the  Eyes 

point  in  the  other  retina;  and  thus  is  cre- 
ated corresponding  retinal  points.  With- 
out such  common  brain  cell  connection, 
the  binocular  spacial  pole,  meridians  and 
parallels  would  be  impossible,  for  there 
could  be  no  corresponding  retinal  points. 
This  condition  is  not  uncommon,  and  over 
such  eyes  the  law  of  binocular  rotations 
has  no  power. 

Ocular  rotations,  whether  monocular  or 
binocular,  can  not  be  understood  except  in 
the  light  of  the  two  planes  of  reference 
shown  in  Fig.  4  on  page  18.  These  two 
planes  are  the  fixed  vertical  and  hori- 
zontal planes  of  the  head,  the  one,  g-h-i-j, 
being  half-way  between  the  centers  of  the 
two  eyes,  the  other,  a-b-c-d,  cutting  the 
centers  of  the  two  eyes.  As  their  names 
imply,  these  two  planes  are  at  right  an- 
gles to  each  other.  The  other  plane, 
k-l-m-n,  shown  in  Fig.  4,  is  Listing's  plane, 
which  is  neither  a  plane  of  reference  nor 
is  it  a  plane  containing  the  axes  of  rota- 
tions, as  was  once  taught.  The  line  e-f 
is  made  by  the  intersection  of  the  two 
planes  of  reference.  From  the  point  /  may 
be  studied  the  four  cardinal  directions,  c 
and  d,  directly  to  the  left  and  right,  in 
the  horizontal  plane ;  and  i  and  j,  directly 
above  and  below,  in  the  vertical  plane. 
Points  not  in  one  or  the  other  of  these 
planes  are  obliquely  related  to  the  line  of 


The  Nervo-Muscular  Mechanism  of  the  Eyes    13 

their  intersection.  The  shifting  of  the 
visual  axes  in  either  one  of  these  planes 
is  the  result  of  a  cardinal  rotation;  when 
the  visual  axes  are  made  to  movo  out  of 
these  planes,  the  rotation  is  oblique.  Fig. 
1  on  page  15  represents  a  horizontal  car- 
dinal rotation;  Fig.  2  represents  a  verti- 
cal cardinal  rotation;  while  Fig.  3  repre- 
sents an  oblique  rotation.  To  these  figures  ref- 
erence will  again  be  made  after  a  study  of  the 
ocular  muscles  and  the  nerve  centers  controll- 
ing them. 

The  ocular  muscles,  as  to  their  origin, 
course  and  insertion,  or  attachment  to  the 
eye,  are  too  well  known  to  require  study 
here.  The  six  muscles  of  each  eye  are  di- 
visible into  three  pairs  as  follows:  (1)  the 
externus  and  the  internus;  (2)  the  supe- 
rior and  the  inferior  recti;  and  (3)  the 
superior  and  inferior  obliques.  If  there 
were  but  one  eye,  the  posing  of  the  head 
would  make  it  unimportant  td  study  the 
first  and  second  grouping;  but  the  third 
grouping,  even  then,  should  not  be  ig- 
nored, for  the  reason  that  no  posing  of 
the  head  would  greatly  help  them,  if  un- 
balanced in  tonicity,  in  their  work  of  al- 
ways keeping  the  vertical  axis  of  the  eye 
parallel  with  the  median  plane  of  the 
head. 

In  this  grouping  the  two  muscles  of  a 
pair  are  related  to  each  other  as  to  tonic- 


14    The  Nervo-Museular  Mechanism  of  the  Eyes 

ity  and  not  as  to  contractility.  Hence 
each  pair  should  be  studied  when  neither 
muscle  is  under  the  active  control  of  any 
brain  center.  Such  study  is  impossible, 
if  there  is  but  one  eye.  Fortunately  it  is 
a  matter  of  no  consequence,  when  there 
is  but  one  eye, .  whether  the  first  or  the 
second  pair  are  equal  or  unequal  in  toni- 
city. In  binocular  vision  it  is  of  im- 
mense importance  to  know  if  the  two  mus- 
cles of  any  one  of  the  three  pairs  are  of 
equal  or  unequal  tonicity;  that  is,  are  they 
orthophoric  or  heterophoric?  This,  as  to 
the  recti,  best  can  be  answered  only  when 
the  two  eyes  are  dissociated  in  action  by 
ciated  by  means  of  the  cyclophorometer. 
means  of  the  monocular  phorometer;  and 
as  to  the  obliques,  when  they  are  disso- 
The  oculist  who  neglects  such  a  study  of 
the  ocular  muscles  is  unjust  to  himself  and 
cruel  to  his  patients. 

Great  as  is  the  temptation  to  enter  here 
into  a  full  study  of  this  feature  of  muscle 
problems,  I  must  not  yield,  as  time  will 
not  allow.  I  have  heard  otherwise  well- 
informed  men  boast  of  their  ignorance  of 
heterophoric  conditions;  but  that  boast 
would  not  now  be  a  badge  of  respectabil- 
ity. 

In  our  study  of  Charts  1,  2,  and  3  we  will 
see  the  wonderful  provision  in  the  brain  for  the 
helpfulness  of  eyes,  in  the  work  of  binoc- 


The  Nervo-Muscular  Mechanism  of  the  Eyes    15 

ular  single  vision,  whose  muscles,  in  one 

or  all  of  the  three  pairs,  are  heterophoric. 

In  the  next  grouping  of  the  ocular  mus- 


Fig.  I. 


cles  in  pairs,  the  one  muscle  of  every  pair 
will  belong  to  one  eye  while  the  other  mus- 
cle of  the  pair  will  belong   to    the    other 


16    The  Nervo-Muscular  Mechanism  of  the  Eyes 

eye.  In  this  grouping  the  muscles  will 
be  studied  in  action  and  not  in  a  state  of 
rest.     There  are  nine  pairs:      (1)  the  two 


Fig.  II. 


superior  recti  for  rotating  the  two  eyes 
directly  upward;  (2)  the  two  inferior 
recti  for  rotating  the  two  eyes  directly 


The  Nervo-Muscular  Mechanism  of  the  Eyes    17 

downward  (these  two  rotations  will  be 
around  the  horizontal  axis  of  the  eye,  but 
with  torsion  which  must  be  prevented  by- 


Fig,  in. 

associated  action  of  two  pairs  of  the  ob- 
liques) ;  (3)  the  two  interni  for  converg- 
ing the  eyes  on  an  object  near  bv  (with- 

2 


18    The  Nervo-Muscular  Mechanism  of  the  Eyes 


out  torsion  if  the  near  point  be  in  the  ex- 
tended horizontal  plane  of  the  head)  ;  (4) 
the  right  externus  and  the  left  internus, 
for  effecting  the  right  cardinal  rotation; 
(5)  the  left  externus  and  the  right  inter- 
nus, for  effecting  the  left  cardinal  rota- 


Fig.  IV. 

tion  (these  two  rotations  will  be  around 
the  vertical  axis  of  the  eye  without  tor- 
sion) ;  (6)  the  two  superior  obliques  for 
aiding  the  two  inferior  recti  in  the  down- 
ward cardinal  rotation,  their  chief  work 
being  to  maintain  the  parallelism  of  the 
two  vertical  axes  with  the  median  plane  of 
the  head;  (7)  the  two  inferior  obliques  to 
aid  the  two  superior  recti  in  the  upward 
cardinal  rotation,  their  chief  work  being 


n 


oj    r-    or    ©    ©  — 


U 

a 

u 


o 


OJ 


22    The  Nervo-Muscular  Mechanism  of  the  Eyes 

to  prevent  the  loss  of  parallelism  between 
the  vertical  axes  of  the  eyes  and  the  me- 
dian plane  of  the  head;  (8)  the  superior 
oblique  of  the  right  eye  and  the  inferior 
oblique  of  the  left  eye  to  maintain  paral- 
lelism of  the  vertical  axes  of  the  eyes 
with  the  median  plane  of  the  head,  in 
every  rotation  obliquely  up  and  to  the 
right  or  down  and  to  the  left;  (9)  the  su- 
perior oblique  of  the  left  eye  and  the  in- 
ferior oblique  of  the  right  eye  to  prevent 
loss  of  parallelism  of  the  vertical  axes  of 
the  eyes  with  the  median  plane  of  the 
head,  in  every  rotation  of  the  eyes  ob- 
liquely up  and  to  the  left  or  down  and  to 
the  right.  Of  these  nine  pairs,  five  are 
of  recti  muscles  and  four  are  of  oblique 
muscles. 

In  the  grouping  of  the  ocular  muscles 
into  active  pairs,  as  above,  each  pair  is 
under  the  volitional  control  of  one  conju- 
gate center.  These  centers,  nine  in  all, 
can  be  studied  in  Charts  1  and  2  in  connection 
with  any  one  of  the  several  plates,  but 
preferably  in  connection  with  that  plate 
not  numbered.  In  orthophoric  eyes  no 
other  brain  centers  are  needed  in  the  four 
cardinal  rotations  and  in  convergence.  In 
every  oblique  rotation  of  orthophoric  eyes 
other  centers  are  needed  in  the  interest 
of  binocular  single  vision.  These  centers 
are  necessary   for    all    heterophoric  eyes, 


The  Nervo-Muscular  Mechanism  of  the  Eyes   23 

whether  at  rest  or  in  motion.  These  cen- 
ters are  at  the  base  of  the  brain,  and  each 
is  connected  with  only  a  single  muscle. 
They  are,  therefore,  twelve  in  number,  six 
being-  on  each  side  of  the  brain.  The  fu- 
sion faculty  of  the  mind — not  volition — 
presides  over  these  centers  and  they  are 
made  to  serve  in  the  interest  of  binocular 
single  vision  and  correct  orientation. 

Cardinal  rotations  of  orthophoric  eyes 
are  easier  than  oblique  rotations,  for  the 
reason  that  basal  or  fusion  centers  have 
nothing  to  do  in  the  former,  while  two 
of  these  centers  are  necessarily  in  action 
in  every  oblique  rotation.  In  hetero- 
phoric  conditions,  two  or  more  of  the  basal 
centers  are  constantly  in  a  state  of  activ- 
ity, whether  the  eyes  be  in  rotation  or  at 
rest — unacted  on  by  any  conjugate  center. 
The  brain  centers  that  are  chargeable 
with  the  "wear-and-tear"  of  eye  strain  are 
the  basal  or  fusion  centers.  The  conju- 
gate or  volitional  brain  centers  neither 
cause  heterophoric  conditions  nor  do  they 
attempt  to  correct  them. 

All  the  brain  centers  controlling  the  oc- 
ular muscles  belong  to  one  of  two  groups : 
First,  the  cortical  centers,  which  are  un- 
der the  control  of  volition.  The  cells  of 
all  these  centers  are  diaxonic,  one  axone 
going  to  one  muscle  of  a  pair,  while  the 
other  axone  goes  to  the  other  muscle  of 


24    The  Nervo-Musculor  Mechanism  of  the  Eyes 

that  pair.  The  second  group  consists  of 
centers  located  at  the  base  of  the  brain, 
all  the  cells  of  which  are  monaxonic,  each 
center  having  under  its  control  only  one 
muscle.  These  centers  are  all  presided 
over  by  the  fusion  faculty  of  the  mind. 

The  cortical  centers  are  properly  called 
conjugate  centers,  since  each  directs  the 
rotation  of  the  two  eyes.  They  are  also 
called  verting  centers,  since  it  is  neuricity 
from  one  or  other,  or  at  most  three,  of 
these,  that  causes  the  turning  of  the  two 
eyes  from  one  point  of  view  to  another. 
Since  the  point  of  view  is  changed  only  as 
one  wills  to  do  so,  another  appropriate 
name  is  volitional  centers. 

These  centers  can  best  be  studied  in  the  plates 
collected  in  Charts  1  and  2,  in  which  they  are 
shown  schematically.  Take  the  uncomplicated 
plate,  unnumbered,  in  Chart  2,  for  this  purpose. 
Eleven  cortical  centers  are  shown  on  each 
side  of  the  brain.  The  centers  10  and  11 
do  not  belong  to  the  extrinsic  ocular  mus- 
cles, but  to  the  sphincters  of  the  iris  and 
the  ciliary  muscles.  That  leaves  nine  cen- 
ters for  the  recti  and  the  obliques.  This 
number  corresponds  precisely  with  the 
number  of  pairs  into  which  we  have  found 
the  muscles  of  the  two  eyes  grouped. 
There  is,  therefore,  one  conjugate  center 
for  each  pair.  These  centers  and  their 
respective  pairs  of  muscles  are  numbered 


The  Nervo-Muscular  Mechanism  of  the  Eyes   25 

in  harmony  in  order  to  make  their  study 
most  easy. 

A  glance  at  the  unnumbered  plate  will 
show  eighteen  conjugate  centers,  nine  of 
which  are  represented  by  large  circles, 
while  the  remaining  nine  are  represented 
by  small  circles.  Eight  of  the  nine  large 
circles  (1  to  9,  except  5),  in  this  and  in 
all  the  plates  in  charts  are  in  the  left  side 
of  the  brain,  while  the  remaining  large 
circle  (5)  stands  alone  in  the  right  side 
of  the  brain.  The  large  circles  represent 
the  active  conjugate  centers  in  control  of 
the  nine  pairs  of  extrinsic  ocular  muscles. 
The  other  small  circles,  eight  of  which  (1 
to  9,  except  5),  are  in  the  right  brain, 
while  the  other  one  (5)  is  in  the  left 
brain,  represent  the  conjugate  centers  that 
would  have  controlled  the  nine  pairs  of 
the  extrinsic  ocular  muscles,  if  the  cause 
determining  which  group  of  nine  centers 
should  be  active,  had  been  in  their  favor. 

At  birth  every  one  of  the  eighteen  con- 
jugate centers  (1  to  9  on  each  side)  stands 
equally  ready  for  action,  and  the  diaxones 
of  all  the  cells  of  all  these  centers  enter 
into  the  formation  of  the  three  pairs 
(third,  fourth  and  sixth)  of  motor  nerves, 
by  means  of  which  the  muscles  are  con- 
nected with  their  respective  centers.  One- 
half  of  these  axones  are  to  be  forever  in- 
active, as  if  dead  wires,  for  the  nine  cen- 


26    The  Nervo-Muscular  Mechanism  of  the  Eyes 

ters  from  which  they  go  will  never  become 
generators  and  dischargers  of  neuricity. 

The  cause  that  determines  which  nine 
conjugate  centers  shall  have  control  of  the 
extrinsic  ocular  muscles  (also  determin- 
ing whether  the  right  or  left  tenth  and 
eleventh  conjugate  centers  shall  control 
the  ciliary  muscles  and  the  pupil  contract- 
ors) is  anatomic.  If  the  diaxonic  visual 
cells  connected  with  the  two  maculas  are 
located  in  the  left  cuneus,  all  the  active 
conjugate  centers,  except  the  fifth,  will 
be  in  the  left  brain,  as  shown  in  all  the 
plates  of  Charts  1  and  2.  The  same  condition 
also  predetermines  the  location  of  the  ac- 
tive speech  center  in  the  left  brain.  Such 
a  person  is  predestined  to  be  right-hand- 
ed; and  the  higher  faculties  of  his  mind 
will  use  only  the  left  side  of  the  brain. 
The  reverse  of  all  this  would  be  true  if  the 
diaxonic  visual  cells  connected  with  the 
two  maculas  were  located  in  the  right 
cuneus.  In  such  a  person  the  only  active 
conjugate  center  in  the  left  brain  would 
be  the  fourth.  The  left  fourth  and  the 
right  fifth  conjugate  centers  are  always 
active,  whether  the  person  be  right-  or 
left-handed. 

The  fusion  centers,  twelve  in  number, 
one  for  each  ocular  muscle,  exist  in  the 
interest  of  binocular  single  vision.  All 
these  are  ready  for  action  at  birth,  and 


The  N  ervo -Muscular  Mechanism  of  the  Eyes   27 

each  one  always  remains  ready  to  store 
and  discharge  neuricity  to  the  muscle  to 
which  it  belongs  when  that  muscle  must 
contract  in  order  that  diplopia  may  be 
prevented,  and  orientation  may  be  correct. 
In  orthophoric  eyes  oblique  rotations  could 
not  be  accomplished,  and  single  vision  be 
maintained,  without  the  aid  of  two  of  the 
twelve  fusion  centers.  In  heterophoric 
eyes  there  would  be  diplopia  whether  the 
eyes  were  at  rest  or  in  motion,  were  it  not 
for  these  fusion  centers.  The  nature  of 
the  imbalance  determines  which  of  these 
centers  shall  be  in  constant  action  —  in 
esophoria,  the  right  and  left  fourth;  in 
exophoria,  the  right  and  left  third ;  in  left 
hyperphoria  and  right  cataphoria,  the 
right  first  and  the  left  second,  and  so'  on. 
Imbalance  of  each  of  the  three  pairs  of 
muscles  would  keep  in  constant  activity 
six  of  the  twelve  basal  centers.  Untreated 
heterophoria  means  perpetual  action  of 
two  or  more  of  these  basal  centers,  dur- 
ing all  waking  hours,  and  in  both  distant 
and  near  seeing.  Such  centers  and  their 
respective  muscles  get  no  rest  except  in 
sleep,  or  when  one  eye  is  covered  or  vol- 
untarily closed.  In  lateral  heterophoria  a 
posing  of  the  head  may  bring  rest  to  one 
basal  center,  but  it  will  demand  greater 
activity  on  the  part  of  the  other  one, 
whether  these  centers  be  the  right  and  left 


28    The  Nervo-Muscular  Mechanism  of  the  Eyes 

third  or  the  right  and  left  fourth  basal 
centers. 

It  is  no  longer  any  wonder  that  many 
people,  who  have  lost  one  eye,  claim  that 
the  remaining  eye  is  stronger  than  the  two 
eyes  ever  were.  Such  people  were  heter- 
ophoric  and  their  fusion  centers  had  no 
longer  any  occasion  for  either  storing  or 
discharging  neuricity,  after  the  loss  of  one 
eye. 

Conjugate  centers,  .as  already  stated, 
are  never  called  on  for  the  correction  of 
heterophorias,  for  this  must  be  done  by 
the  fusion  centers.  There  are  conditions, 
however,  that  make  excessive  demands  on 
the  conjugate  centers.  These  conditions 
can  only  be  named  here:  asthenic  ortho- 
phoria and  asthenic  heterophoria  of  what- 
ever kind.  Sthenic  orthophoria  and  the 
sthenic  heterophorias  make  less  than  the 
normal  demand  on  the  conjugate  centers. 

In  the  following  study  of  the  structure 
of  the  three  pairs  of  motor  nerves  of  the 
eyes,  these  must  be  considered  as  belong- 
ing to  a  person  who  is  right-handed,  whose 
macular  connections  are  all  in  the  left 
brain.  Plate  1  shows  that  conjugate  cen- 
ters 1,  2,  3,  7,  9,  10  and  11,  in  the  left  brain, 
send  forth  their  fibers  across  the  median 
line  to  help  form  the  right  third  nerve, 
and  that  conjugate  center  5  in  the  right 
brain  sends  direct  fibers  to  help  form  this 


The  Ncrvo-Muscular  Mechanism  of  the  Eyes   29 

nerve.  Only  half  the  axones  from  these 
eight  conjugate  centers  are  thus  directed. 
The  other  half  of  the  axones  from  the  cen- 
ters named,  except  the  fifth,  enter  into  the 
formation  of  the  left  third  nerve  (See 
Plate  2),  and  in  this  nerve  will  be  found 
half  the  axones  from  the  left  fourth  con- 
jugate center.  None  of  the  fibers,  or  ax- 
ones, forming  the  left  third  nerve  have 
crossed  from  the  opposite  side  of  the  brain. 
The  balance  of  the  right  third  nerve  is 
formed  by  all  the  single  axones  of  right 
basal  centers  1,  2,  3,  7,  10  and  11;  and  the 
balance  of  the  left  third  nerve  is  composed 
of  all  the  fibers  from  the  left  1,  2,  3,  7,  10 
and  11  basal  centers.  Thus,  it  will  be 
seen,  that  each  third  nerve  is  composed  of 
half  the  fibers  from  eight  conjugate  cen- 
ters and  all  the  fibres  from  six  basal  cen- 
ters. 

The  construction  of  the  fourth  pair  of 
nerves  is  very  simple,  as  shown  in  Plates 
3  and  4  of  Chart  1.  The  right  fourth 
has  in  it  half  the  axones  from  the  left 
six  and  eighth  conjugate  centers  and  all 
the  axones  from  the  right  sixth  basal  cen- 
ter. The  left  fourth  nerve  is  composed 
of  half  the  axones  from  the  left  sixth  and 
ninth  conjugate  centers  and  all  the  axones 
from  the  left  sixth  basal  or  fusion  center. 
All  the  volitional  fibers  of  the  right  fourth 
nerve  have  crossed,  as'*  shown  in  Plate  3; 


30    The  Nervo-Muscular  Mechanism  of  the  Eyes 

while  none  of  those  forming  the  left  fourth 
nerve,  as  shown  in  Plate  4,  have  crossed. 

The  construction  of  the  sixth  pair  of 
nerves  is  still  less  complicated.  Plate  5 
shows  the  right  sixth  nerve  composed  of 
half  the  axones  from  th^  left  fourth  con- 
jugate center  and  all  the  axones  from  the 
right  fourth  basal  or  fusion  center.  Plate 
6  shows  the  left  sixth  nerve  composed  of 
half  the  axones  from  the  right  fifth  con- 
jugate center,  and  ail  the  axones  from  the 
left  fourth  basal  or  fusion  center.  All 
the  voluntary  fibers  found  in  either  of  the 
two  sixth  nerves  have  crossed  on  their  way 
from  center  to  muscle.  None  of  the  fu- 
sion fibers  of  any  one  of  the  three  pairs 
of  motor  nerves  have  crossed  to  the  oppo- 
site side.  All  the  fibers  or  axones  enter- 
ing into  the  formation  of  these  nerves  are 
insulated  from  their  starting  point,  the 
central  cell,  to  their  termination  In  the 
muscles,  so  that  the  neuricity  generated 
by  these  cells  may  not  be  dissipated  when 
discharged  to  the  muscles  for  controlling 
them  in  their  action. 

The  active  fusion  centers  in  the  several 
forms  of  heterophoria  are  shown  in  the  plates 
of  Chart  3,  and  the  last  plate  in  Chart  2.  The 
unnumbered  plate  in  Chart  2  shows  the  fact 
that,  in  orthophoria,  there  is  no  excitation  of 
either  conjugate  or  fusion  centers  when 
the  point  of  view  is  straightforward  and, 


The  Ncrvo-Muscular  Mechanism  of  the  Eyes   31 

practically,  at  infinity.  Both  brain  rest 
and  muscle  inaction  are  shown  in  this 
plate  by  the  absence  of  all  connecting 
fibers. 

Plate  25  shows  the  two  fusion  centers 
that  must  be  unremittingly  active  in  left 
hyperphoria  and  right  cataphoria.  These 
are  the  right  first  and  left  second  fusion 
centers  acting,  respectively,  on  the  right 
superior  and  left  inferior  rectus.  If  the 
condition  were  right  hyperphoria  and  left 
cataphoria,  the  excited  fusion  centers 
would  be  the  left  first  and  the  right  sec- 
ond, and  the  constantly  contracting  mus- 
cles would  be  the  left  superior  and  right 
inferior  recti. 

Plate  21  shows  the  excited  fusion  cen- 
ters and  the  contracting  muscles  in  ex- 
ophoria,  while  Plate  17  shows  the  over- 
worked fusion  centers  and  their  respective 
muscles  in  esophoria.  Plate  36  illustrates 
the  brain  and  muscle  activity  in  plus  cy- 
clophoria,  while  Plate  37  shows  the  fusion 
centers  and  the  two  muscles  which  are  in 
constant  action  in  minus  cyclophoria. 
These  heterophorias  successfully  treated 
by  operation  or  other  means  would  give 
to  brain  centers  and  muscles  the  restful 
state  shown  in  the  unnumbered  plate. 
Untreated,  the  wear-and-tear  of  brain  and 
muscles  must  go  on  to  the  end  of  life. 

Before  closing  with  the  study  of  rota- 


32    The  Ncrvo-Muscular  Mechanism  of  the  Eyes 

tions,  the  muscles  and  brain  centers  con- 
cerned in  each,  the  laws  of  motion  must 
be  given. 

LAW  OF  MONOCULAR  MOTION 

The  law  governing-  monocular  rotations 
may  be  formulated  as  follows: 

"(1)  The  visual  axis,  which  is  the  line 
of  intersection  of  the  planes  of  all  me- 
ridians, must  be  rotated  in  the  plane  of 
that  meridian  on  tvhich  lie  the  first  and 
second  points  of  view  and  their  retinal 
images. 

"(2)  In  the  plane  of  the  horizontal, 
or  that  of  the  vertical  meridian,  the  rota- 
tion must  be  effected  around,  a  single  fixed 
axis,  at  right-angles  to  the  rotation  plane 
and  cutting  it  at  the  center  of  rotation  — 
if  in  the  horiontal  plane,  around  the  verti- 
cal axis  of  the  eye;  if  in  the  vertical  plane, 
around  the  transverse  axis  of  the  eye. 

"(3)  In  the  plane  of  an  oblique  rotation, 
whatever  the  degree  of  obliquity,  the  rota- 
tion must  be  accomplished,  around  two 
moving  axes  by  two  forces  acting  simul- 
taneously, these  axes  being  the  transverse 
and  vertical  axes,  both  at  right-angles  to 
the  visual  axis,  but  neither  one  at  right- 
angles  to  any  oblique  rotation  plane;  while 
a  third  force  prevents  any  rotation  around 
the  visual  axis." 

The  law   of  monocular    motion,    since 


The  Nervo -Muscular  Mechanism  of  the  Eyes   33 

binocular  vision  is  not  in  consideration,  is 
accomplished  without  any  demand  on  the 
fusion  centers,  just  as  in  monocular  rest 
there  is  no  such  demand. 

LAW   OF   BINOCULAR   ROTATIONS 

In  binocular  rotations  each  eye  must 
obey  the  law  of  monocular  motion,  but  the 
two  together  must  obey  the  laiv  of  binocu- 
lar rest  and  motion.  "The  twelve  extrin- 
sic muscles  of  normal  eyes  under  the  con- 
trol of  the  nine  conjugate  and  the  twelve 
fusion  brain  centers,  must  so  relate  the 
two  eyes  that  their  two  visual  axes  and 
the  two  horizontal  retinal  meridians  shall 
always  lie  in  the  plane  of  the  primary 
isogonal  circle,  whether  at  rest  or  in  mo- 
tion, and  that  the  two  visual  axes  shall 
converge  at  some  point  on  this  circle,  in 
the  interest  of  both  binocular  single  vision 
and  correct  orientation" 

Binocular  rotations  can  best  be  stud- 
ied in  the  light  of  Fig.  4.  In  this  study 
the  two  eyes  will  be  considered  as  or- 
thophoric.  The  line  e-f  of  intersection  of 
the  two  planes  of  reference  is  the  line 
on  which  every  object  or  point  must  be 
located  which  is  to  be  considered  the  pri- 
mary point  of  view.  If  this  point  is  at 
infinity,  the  conjugate  and  the  fusion 
brain  centers  and  all  the  ocular  muscles 
are  in  a  state  of  rest.  If  the  point  is  near 
3 


34    The  Nervo-Muscular  Mechanism  of  the  Eyes 

by,  only  two  extrinsic  muscles  (the  inter- 
ni)  and  one  conjugate  brain  center  (the 
third)  are  in  action. 

Objects  or  points  in  space  not  on  the 
line  e-f  are  secondary  points  of  view.  If 
these  points  are  in  either  the  horizontal 
or  the  vertical  plane  of  reference,  they 
are  cardinally  related  to  points  on  the  line 
e-f.  Points  not  in  either  of  these  planes 
are  obliquely  related  to  their  line  of  inter- 
section, e-f. 

The  points  c  and  d  are  in  the  horizontal 
plane  with  /.  In  moving  the  visual  axes 
from  /  to  d,  the  fourth  conjugate  center 
and  the  right  externus  and  left  internus 
are  active,  and  each  eye  is  rotated  around 
its  vertical  axis.  All  other  centers  and 
muscles  are  at  rest  in  this  rotation.  In 
moving  the  visual  axes  from  f  to  c  the 
fifth  conjugate  center  sends  neuricity  to 
the  left  externus  and  right  internus.  In 
cardinal  rotations,  right  or  left,  only  two 
muscles  are  called  into  action  by  only  one 
conjugate  center.  The  right  rotation  is 
shown  in  Fig.  1. 

Points  i  and  /  are  in  the  vertical  plane 
of  the  head  with  point  /.  In  rotation  of  the 
visual  axes  from  /  to  i  two  pairs  of  mus- 
cles and  two  conjugate  centers  will  be 
called  into  action  by  the  will.  One  pair 
of  the  muscles  is  the  two  superior  recti 
and  the  other,  the  two  inferior  obliques. 


The  Nervo-Muscular  Mechanism  of  the  Eyes   35 

The  centers  calling  these  muscles  into  ac- 
tion are,  respectively,  the  first  and  sev- 
enth conjugate  centers.  This  rotation  is 
shown  in  Fig.  2.  The  rotation  from  /  to  j 
would  be  effected  by  the  two  inferior  recti 
and  the  two  superior  obliques,  under  the 
influence,  respectively,  of  the  second  and 
sixth  conjugate  centers.  In  both  of  these 
cardinal  rotations  of  orthophoric  eyes, 
all  other  ocular  muscles  and  brain  centers, 
not  named  in  that  connection,  are  at  rest. 
These  rotations  are  around  the  horizontal 
axis  of  the  eye. 

A  point  anywhere  above  the  horizontal 
plane  and  to  the  right  of  the  vertical 
plane,  obliquely  related  to  point  /,  can  be 
reached  by  the  two  visual  eyes  only  by  the 
harmonious  action  of  three  pairs  of  mus- 
cles— the  two  superior  recti,  the  right  ex- 
ternus  and  left  internus,  and  the  right  su- 
perior oblique  and  left  inferior  oblique — 
and  by  three  conjugate  centers,  respec- 
tively, the  first,  the  fourth,  and  the  eighth. 
All  other  muscles  and  conjugate  centers 
are  inactive.  Two  fusion  centers,  the 
right  first  and  the  left  third,  must  aid  in 
this  rotation.  This  rotation,  as  shown  in 
Fig.  3,  and  all  other  oblique  rotations  are 
effected  around  two  moving  axes,  the  ver- 
tical and  horizontal  axes,  by  means  of 
three  pairs  of  muscles  acted  on  by  their 
respective  conjugate  centers,  aided  by  two 


36    The  Nervo-Muscular  Mechanism  of  the  Eyes 

fusion  centers.  The  rotation  shown  in 
Fig.  3  is  an  example  of  all  oblique  rota- 
tions. 

All  oblique  rotations  are  around  the 
same  two  axes,  each  moving  as  the  eye 
rotates  around  the  other.  These  two  axes 
are  the  vertical  and  horizontal  axes  of 
the  eyes,  and  these  are  the  axes  of  the 
four  cardinal  rotations,  though  in  either 
of  the  latter  there  is  but  one  axis  and  it 
is  fixed  throughout  the  given  rotation. 

The  aim  of  the  treatment  of  all  forms 
of  heterophoria  is  to  make  it  easy  for  the 
eyes  to  obey  the  law  of  binocular  rest  and 
motion. 


ROUTINE  IN  EYE  WORK* 

The  title  of  my  address  presupposes  prepared- 
ness for  practice.  The  past,  in  many  instances, 
would  not  justify  this  presumption,  for  it  has 
been  notorious  that  "  the  six-weeks'  postgraduate 
course  "  has  plunged  many  a  man  into  eye  work 
without  proper  preparation.  As  out  of  the  old- 
time  medical  course  of  two  years,  which  never 
did  fit  one  for  the  practice  of  medicine  and  sur- 
gery, there  occasionally  grew  giants — such  as 
Flint,  Gross,  and  others — so  out  of  a  course  in 
ophthalmology  all  too  short  there  have  sprung 
some  men  of  might  in  our  specialty.  The  real 
preparation  of  these  men  began  after  their  short 
courses  of  study,  under  teachers,  had  ended,  and 
was  carried  on  by  dint  of  personal  effort  in  pri- 
vate study  and  meditation,  long  continued. 

"  The  heights  by  these  men  reached  and  kept 
Were  not  attained  by  sudden  flight; 
But  they,  while  many  comrades  slept, 
Were  toiling  upward  in  the  night." 

Times  are  changing,  and  the  near  future  will 
reveal  a  more  perfect  preparation  on  plans  more 
practical.    Rules  for  governing  the  future  teach« 


•Chairman's  address,  read  before  the  Section  on  Eye,  Ear, 
Nose,  and  Throat  at  the  annual  meeting  of  the  Tennessee  Stat* 
Medical  Association,  Knoxville,  April,   1916. 


38  Routine  in  live  Work 

ing  of  ophthalmology  are  now  being  formulated 
by  committees  from  the  American  Ophthalmo- 
logical  Society,  the  Section  of  Ophthalmology  of 
the  American  Medical  Association,  and  the  Acad- 
emy of  Ophthalmology  and  Oto-Laryngology. 
The  joint  report  of  these  committees,  doubtless, 
will  demand  that  only  graduates  in  medicine 
shall  be  permitted  to  enter  a  specific  and  pro- 
longed course  in  ophthalmology,  in  a  medical  in- 
stitution authorized  by  law  to  confer  degrees, 
and  that  only  such  a'  degree  will  entitle  an  appli- 
cant to  the  privilege  of  an  examination  by  a 
properly  constituted,  lawful  national  board  of 
examiners,  whose  certificate  would  give  him  the 
legal  right  to  practice  in  any  state  of  our  Union. 

We  who  are  already  in  the  practice  need  not 
be  troubled  because  of  any  demands  to  be  made 
on  us,  for  the  new  rules  will  not  be  retroactive; 
but  we  may  well  fear  the  competition  of  the 
products  of  future  teaching,  unless  we  ourselves 
become  better  grounded  in  the  principles  of 
ophthalmology  and  more  fully  equipped  for  its 
practice. 

There  is  no  specialty  in  medicine  and  surgery 
comparable  to  ours  in  scientific  depths  and  in 
practical  heights.  The  scientific  principles  can 
be  found  in  their  beauty  and  strength  only  by 
deep  digging;  the  practical  heights   can  be  at- 


Routine  in  Eye  Work  39 

tained  only  by  him  who  is  willing  to  climb,  and 
to  keep  on  climbing,  though  he  may  have  stum- 
bled often. 

Whether  one  gets  into  the  practice  of  ophthal- 
mology through  the  short  route  of  the  past,  and 
straight  because  so  short,  or  through  the  longer 
and  devious  road  of  the  future,  if  he  wishes  for 
the  best  success,  he  must  be  a  routinist  as  to 
methods  and  means.  Routine  in  eye  work  does 
not  mean  that  one  should  never  change  from  a 
method,  or  plan,  of  work,  unless  that  method, 
or  plan,  be  perfect.  One  routine  should  be  to 
change  from  worse  to  better  at  every  opportu- 
nity. There  are  some  perfected  methods  of  do- 
ing eye  work,  and  there  are  some  means  at  our 
command  that  cannot  be  improved.  I  wish  I 
might  be  able  to  say  this  of  all  methods  and  of 
every  means ;  but  this  cannot  be  said  until  oph- 
thalmology, both  as  a  science  and  as  an  art,  has 
reached  perfection. 

The  relationship  between  the  practitioner  and 
the  patient  sometimes  begins  when  the  one  has 
never  seen  the  other,  the  medium  between  the 
two  being  the  written  letter.  The  letter,  long  or 
short,  well  written  or  badly  composed,  pertinent 
or  impertinent,  pointed  or  without  point,  de- 
mands an  answer.  The  reply  should  disclaim 
any  ability  to  make  a  diagnosis  without  a  per- 


40  Routine  in  Eye  Work 

sonal  investigation,  but  should  express  a  will- 
ingness to  do  everything  possible  for  the  relief 
of  such  condition  as  might  be  found  on  careful 
examination.  Any  suggestion  as  to  "  absent 
treatment  "  should  be  courteously  declined  as  a 
thing  improper  and  impossible.  An  early  visit 
may  be  suggested  or  even  urged,  for  the  condi- 
tion may  be  serious.  Unless  the  patient's  letter 
contains  a  direct  question  as  to  fee,  the  reply 
should  make  no  mention  of  it.  If  there  be  a  di- 
rect question  as  to  the  fee  for  examination  and 
advice,  the  amount  should  be  named  for  such 
preliminary  examination  as  would  justify  a  diag- 
nosis and  include  a  prescription  if  needed.  The 
letter  should  state  that  the  charge  for  a  more 
extended  service,  or  an  operation,  if  necessary, 
can  be  learned  before  such  service  is  rendered. 
It  is  better  that  this  understanding  should  be 
had  beforehand. 

Uniformity  in  charges  against  those  who  are 
able  to  pay  should  be  a  fixed  routine,  whether 
the  charge  be  named  in  a  letter  or  spoken  in  per- 
son. "  The  same  fee  for  the  same  service  "  is  a 
splendid,  practical  motto.  Any  variation  from 
this  should  be  either  a  professional  courtesy  or 
an  act  of  charity.  The  best  charity  in  this  re- 
spect is  to  allow  the  patient  to  pay  as  much  as 
possible  of  the  regular  charge  and  then  cancel 


Routine  in  Eye  Work  41 

the  remainder.  To  charge  a  higher  fee  than 
usual  because  one  may  be  rich  is  not  good  rou- 
tine. It  is  not  good  even  on  the  ground  that 
this  would  enable  you  to  do  charity  work  for 
others.  Charity  thus  paid  for  by  another  is  no 
charity,  hence  would  not  be  credited  by  the  Re- 
cording Angel. 

The  majority  of  patients  come  without  pre- 
vious announcement,  often  with  the  family  physi- 
cian or  bearing  a  letter  from  him.  If  the  pa- 
tient is  poor  or  in  moderate  circumstances  or 
rich,  it  is  usually  told.  If  poor  and  a  charitable 
consideration  is  suggested,  it  should  be  heeded. 
No  one  can  know  the  financial  condition  of  a 
patient  better  than  the  family  physician.  What- 
ever may  be  the  state  of  finances,  the  patient  who 
has  been  assured  by  the  family  physician  that 
he  or  she  will  be  properly  treated  in  every  re- 
pect  is  not  likely  to  ask  a  question  as  to  the 
charge  until  the  service  has  been  rendered.  Let- 
ters from  physicians  should  be  acknowledged 
with  thanks,  and  they  should  be  told  of  condi- 
tions found  and  of  treatment  instituted  for  the 
relief  of  their  patients.  Many  patients  come 
without  a  letter  of  introduction  and  commenda- 
tion. 

In  whatever  manner  patients  may  come,  they 
should  be  courteously  met  at  the  door  by  the 


4_'  Routine  in  Eye  Work 

office  girl,  who,  after  seating  them,  should  pre- 
sent them  with  a  Keller  book  of  perforated  cards, 
every  other  leaf  of  which  is  nonperforated.  Be- 
tween the  two  leaves  there  should  be  a  carbon 
paper,  with  the  black  face  toward  the  solid  leaf, 
with  a  pencil  provided — better  tied  to  the  book. 
Each  patient  should  be  asked  to  write  his  or  her 
name  and  address  on  the  lowest  card.  The  next 
patient  should  write  on  the  next  card  above,  and 
so  on  until  every  recent  arrival  shall  have  filled 
a  card.  Each  name  should  be  taken  in  the  order 
of  arrival.  The  names  of  attendants  or  chap- 
erons should  not  be  taken.  Whether  one  or  sev- 
eral names  have  been  written,  only  the  filled 
cards  should  be  torn  away.  The  next  duty  of  the 
office  girl  is  to  place  the  cards,  in  the  order  in 
which  they  have  been  filled,  under  the  double 
punch  in  such  a  way  that  one  of  the  holes  to  be 
made  shall  be  close  to  the  right  end  of  the  card. 
On  the  same  board  with  the  punch  there  should 
be  two  uprights,  with  movable  clips  for  opening 
and  closing  them.  The  cards  should  be  filed,  in 
their  proper  order,  on  the  left-  upright,  through 
the  hole  at  the  end  of  the  name  and  close  to  the 
end  of  the  card.  As  others  arrive,  the  same  or- 
der of  procedure  should  follow.  On  this  stand- 
ard will  appear  only  the  names  of  patients  not 
yet  seen.    The  card  that  is  lowest  always  belongs 


Routine  in  Eye  Work  43 

to  the  patient  next  to  be  seen.  The  best  method 
of  procedure  now  is  to  call,  by  bell  tap,  the  office 
girl  to  your  desk,  while  you  pull  the  bottom  card 
loose  from  the  left  standard.  Reading  the  name 
and  address,  you  direct  the  girl  to  bring  that  pa- 
tient in,  while  you  place  the  card  on  the  right- 
hand  standard  through  the  untorn  opening  at 
the  other  end  of  the  card.  Remembering  the 
name,  or  glancing  at  it  again,  you  are  enabled  to 
greet  the  patient  by  name  as  she  enters,  to 
be  seated  near  your  desk. 

This  transference  of  cards  from  one  standard 
to  the  other  is  made,  as  patient  after  patient  is 
seen,  until  every  one  has  been  presented.     As 
each  patient  is  retiring,  the  proper  entering  of 
the  fee  should  be  made  on  the  card,  and  either 
the  word  "  charge  "  or  "  paid  "  should  be  written. 
At  each  subsequent  bell  tap  the  office  girl  could 
bring  the  next  patient,  in  order,  from  the  car- 
bon writing  on  the  solid  leaf,  checking  each  name 
as  the  patient  is  sent  in.     But  this  is  not  the  bet- 
ter routine.     This  would  not  insure  your  having 
looked  at  the  name,  for  you  may  have  failed  to 
transfer  that  patient's  card  from  the  one  stand- 
ard to  the  other;  hence  the  failure  to  greet  by 
name — a  failure  that  would  have  a  bad  effect  on 
a  new  patient  and  a  worse  effect  still  on  an  old 
patient.     The  main  purpose  of  the  carbon  writ- 


44  Routine  in  Eye  Work 

ing  is  that  it  may  be  referred  to  at  any  subse- 
quent time,  and  for  this  reason  every  solid  page 
should  be  dated  at  the  top.  At  the  end  of  every 
day,  after  transferring  all  charges  to  the  blotter 
or  daybook,  the  cards  filed  during  the  day  should 
be  thrown  away. 

The  routine  use  of  the  Keller  registration  book 
produces  the  following  results :  ( 1 )  It  insures 
the  presentation  of  patients  in  the  order  of  ar- 
rival;  (2)  it  enables  the  doctor  to  greet  the  pa- 
tient by  name;  (3)  if  the  patient  is  an  old  one, 
the  record  may  be  looked  into  before  the  presen- 
tation ;  (4)  it  insures  against  failure  to  make  the 
proper  financial  entry ;  (5)  at  the  close  of  the  day 
the  exact  number  of  patients  may  be  known  by 
counting  the  cards ;  (6)  a  permanent  carbon 
copy  of  each  day's  record  is  kept  for  reference. 

When  in  the  consulting  room,  some  patients 
will  hesitate  to  take  the  offered  chair  until  they 
know  something  about  the  cost  of  the  consulta- 
tion. One  question  sometimes  asked  is :  "  Do 
you  charge  anything  for  the  examination  ? " 
This  question,  doubtless,  is  more  often  asked  of 
oculists  than  of  any  other  class  of  physicians,  for 
the  reason  that  so-called  "  oculists  "  advertise : 
"Examinations  free."  The  routine  answer  to 
this  question  should  be :  "  If  I  did  not  charge,  I 
would  have  to  spend  all  my  time  treating  curi- 


Routine  in  Eye  Work  45 

osity."  This  statement,  in  such  cases,  should  be 
immediately  followed  by  the  naming  of  the  usual 
fee  for  a  preliminary  examination.  Only  rarely 
will  such  a  prospective  patient  depart  without  a 
proper  consultation. 

A  large  number  of  patients,  after  being 
seated,  will  ask :  "  Doctor,  what  will  be  your 
charge  for  finding  out  what  my  condition  is,  and 
what  ought  to  be  done  for  me,  for  I  am  not 
sure  that  I  will  want  treatment  to-day  ?  "  They 
should  be  told  the  usual  fee,  which  should  always 
be  uniform,  and  this  charge  should  include  a 
prescription,  should  the  condition  call  for  that 
only.  If  this  investigation  is  carefully  made,  in 
a  routine,  but  thorough,  manner,  the  patient  will 
be  ready  and  willing  to  submit  to  whatever  sub- 
sequent procedure  may  be  advised,  as  soon  as 
the  fee  for  same  may  have  been  named,  whether 
it  be  the  fitting  of  glasses,  operations  on  the 
muscles,  or  other  operative  work. 

A  still  larger  number  of  patients  will  indicate 
that  their  chief  desire  is  to  know^  the  nature  of 
their  cases  and  to  obtain  relief,  willing  to  leave 
the  matter  of  fee  for  the  final  consideration,  hav- 
ing the  conscious  assurance  that  they  will  not  be 
overcharged,  and  this  confidence  should  not  be 
abused. 

Whether  a  patient  belongs  to  one  or  the  other 


46  Routine  in  Eye  Work 

of  these  three  classes,  or  even  if  the  patient  be 
known  to  be  penniless,  the  same  conscientious, 
careful  consideration  should  be  given  to  every 
detail  of  the  investigation.  The  oculist  should 
be  a  good  listener ;  for,  whether  necessary  or 
not,  the  patient  believes  that  the  story  of  suffer- 
ing and  other  facts  of  personal  or  family  history 
should  be  told.  Routine  listening  is  not  dam- 
aged by  a  question  properly  propounded.  The 
question  may  impress  the  patient  that  your  in- 
terest is  deepening;  The  patient's  story  may  be 
cut  short  by  a  very  simple  little  procedure,  which 
may  not  always  be  necessary,  but,  because  of  its 
effectiveness,  should  be  practiced.  It  is  the  pull- 
ing down  of  the  lower  lid,  first  on  one  side  and 
then  on  the  other,  accompanied  by  a  look  into 
the  lower  conjunctival  fold.  If  this  is  found 
perfectly  healthy,  there  is  but  little  need  for 
everting  the  upper  lid ;  but  if  the  lymph  follicles 
are  enlarged,  the  upper  lid  should  be  turned  to 
ascertain  if  trachoma  bodies  are  present.  One 
can  then  proceed  with  the  investigation,  the  pa- 
tient now  being  pleased  to  answer  questions  only. 
The  presence  of  a  pterygium,  corneal  ulcer,  scar, 
or  opacity  can  now  be  noted.  The  size  of  the 
pupil  and  its  reaction  to  light  should  be  observed. 
The  pupil  may  be  found  black  or  hazy,  as  in  cat- 
aract.   No  comment  should  now  be  made  on  any 


Routine  in  Eye  Work  47 

of  these  observations.  If  small,  inactive  pupil, 
circumcorneal,  or  even  general,  redness,  with 
lachrymation,  pain  and  dread  of  light  should  in- 
dicate iritis,  the  touchstone  of  the  investigation 
should  be  applied — atropine  solution  instilled — 
and  the  patient  should  be  sent  to  some  dark  cor- 
ner to  await  the  effect.  No  dilatation  at  all,  or 
irregular  or  jagged  dilatation,  now  justifies  the 
diagnosis  of  iritis.  Not  only  the  diagnosis,  but 
also  the  seriousness  of  the  disease,  should  be 
told;  and  the  routine  treatment  should  be  insti- 
tuted. 

Should  the  pupil  be  dilated,  inactive,  and  ap- 
parently greenish,  whether  redness  or  pain  ex- 
ists or  not,  glaucoma  should  be  suspected.  In- 
creased tension,  whether  shown  to  the  fingers  or 
by  the  tonometer,  would  make  the  case  more 
suspicious ;  but  the  diagnosis  should  not  be  given 
until  the  ophthalmoscope  has  revealed  the  cupped 
disc.  In  giving  the  diagnosis,  the  gravity  of  the 
condition  should  be  mentioned  to  either  the  pa- 
tient or  to  a  relative  or  near  friend.  The  acute- 
ness  of  vision,  if  any,  should  be  noted.  As  in  all 
others,  the  case  history  should  be  taken.  Treat- 
ment suited  to  the  case  should  be  instituted.  Op- 
eration must  be  done  if  the  case  is  acute,  and 
may  be  done  if  the  case  is  subacute  or  chronic. 
Every  operator  should  select  that  method  of  op- 


48  Routine  in  Eye  Work 

erating  which  appeals  to  him  most,  and  should 
do  it  routinely — if  trephining,  by  all  means  tre- 
phine ;  if  LaGrange's  operation,  do  it  constantly ; 
if  the  modified  LaGrange — the  cutting  off  of  the 
corneal  lip — do  it;  if  the  iris-incarceration  op- 
eration, do  it ;  if  the  Graefe  broad  iridectomy,  do 
it.  As  for  myself,  I  prefer  the  modified  La- 
Grange;  and  the  more  often  I  do  it,  the  better 
able  I  am  to  do  it  and  the  more  successful  I  will 
be  in  my  results. 

To  outline  my  routine  in  connection  with  other 
diseases  would  make  this  address  entirely  too 
long.  My  main  purpose,  from  the  beginning, 
was  to  outline  and  emphasize  the  importance  of 
routine  work  in  detecting  and  correcting  errors 
of  refraction  and  muscle  errors. 

In  a  given  case  we  have  found  no  evidence  of 
the  existence  of  any  ocular  disease.  The  patient 
has  given  a  history  pointing  more  or  less  strong- 
ly to  some  visual  defect. 

Routine  work  of  investigation  should  now  be- 
gin. If  not  already  seated  between  the  refrac- 
tion case  and  the  phorometer,  the  patient  should 
be  so  placed.  The  card  of  test  letters  should  be 
immediately  in  front,  and  distant  twenty  feet. 
The  patient  should  now  be  asked  to  read  with 
the  two  eyes  the  smallest  letters  possible  to  her. 
The   result   should  be   noted.      Then   each   eye 


Routine  in  Eye  Work  49 

should  be  tested  alone  in  the  same  manner.  The 
fact  that  vision  with  each  eye  alone  is  20-20  is 
no  evidence  that  hyperopia  does  not  exist  and 
that  astigmatism  is  absent;  but  myopia  and  high 
degrees  of  astigmatism  have  been  eliminated. 
The  next  routine  step  should  be  to  prove  the 
presence  or  absence  of  hyperopia,  and  this  is 
done  by  holding  a  pair  of  spheres,  +2.00  D,  be- 
fore the  eyes  and  noting  the  acuteness  of  vision 
through  them.  If  vision  is  20-20  through  these 
lenses,  there  is  a  high  degree  of  hyperopia ;  and 
if  better  than  20-100,  there  is  more  or  less  hyper- 
opia present  in  one  or  both  eyes.  In  a  case  of 
this  kind  astigmatism  of  low  degree  may  be 
easily  detected  by  means  of  a  pair  of  +.50  D 
cylinders.  If,  with  the  axes  vertical,  the  vision 
is  more  acute  than  when  they  are  horizontal, 
there  is  astigmatism  according  to  the  rule ;  if, 
with  these  cylinders,  with  axes  horizontal,  vision 
is  more  acute  than  when  vertical,  there  is  astig- 
matism against  the  rule.  If,  without  lenses, 
vision  is  low,  it  may  be  due  to  a  very  high  de- 
gree of  hyperopia,  which  would  be  shown  by  the 
fact  that  vision  is  improved  by  strong  plus 
spheres ;  or  it  may  be  chargeable  to  myopia, 
which  will  be  shown  by  more  acute  vision 
through  strong  minus  spheres ;  or  the  low  vision 
may    depend    on    high    degrees    of    astigmatism, 


50  Routine  in  Eye  Work 

which  will  be  shown  by  increased  acuity  of 
vision  through  strong  cylinders,  either  plus  or 
minus,  with  their  axes  in  certain  positions. 

The  routine  of  the  preliminary  examination 
might  end  here  if  the  ciliary  muscles,  as  once 
claimed,  were  Pandora's  box,  out  of  which  come 
all  evils  chargeable  to  the  eyes ;  and  proper  steps 
might  be  taken  at  once  to  prepare  the  patient  for 
the  final  examination,  looking  toward  the  correc- 
tion of  the  focal  errors  just  detected.  If  there 
is  but  one  eye,  the  preliminary  examination  out- 
lined above  is  the  beginning  and  the  end.  Not 
so  when  there  are  two  eyes.  Not  to  go  further 
would  mean  failure  in  a  large  percent  of  cases. 

The  routine  worker  now  turns  from  the  trial 
case  to  the  phorometer,  with  confidence  that  its 
findings  will  help  him  to  render  better  service  to 
his  patient. 

A  word  as  to  the  phorometer  itself  before  put- 
ting it  to  routine  use.  While  on  the  floor  in  Den- 
ver, in  1898,  discussing  the  method  of  determin- 
ing heterophoric  conditions,  I  stated  that  the  per- 
fect phorometer  has  not  yet  been  invented,  but, 
when  invented,  it  would  be  built  on  the  principle 
that  the  retinal  image  in  one  eye  should  be  undis- 
turbed throughout  any  given  test  of  the  other 
eye ;  that  no  binocular  phorometer  is  trustworthy. 
Hesitating  a  moment,  I  said:  "At  this  very  mo- 


Routine  in  Eye  Work  51 

ment  the  monocular  phorometer  has  taken  form 
in  my  mind,  and  as  soon  as  I  return  home  I  will 
have  it  made  and  put  to  the  test."  Many  of  you 
are  acquainted  with  that  device  which  was  made, 
at  my  suggestion,  by  F.  A.  Hardy  &  Co.  in  the 
early  fall  of  1898,  since  which  time,  until  recent- 
ly, it  has  had  no  rival  as  a  monocular  instru- 
ment. While,  through  the  years,  many  have  been 
convinced  that  the  monocular  principle  is  the  cor- 
rect one,  and  that  the  monocular  phorometer  is 
the  only  one  worthy  of  trust,  many  others  have 
held  on  to  the  binocular  idea  and  have  used  only 
the  binocular  instrument.  The  day  for  the  dis- 
card of  the  binocular  phorometer  has  come,  and 
the  monocular  phorometer  is  here  to  reign  for 
all  time.  The  day  of  retirement  of  my  own 
monocular  phorometer  has  come,  and  likewise 
that  of  my  cyclophorometer,  which  of  necessity 
is  a  binocular  instrument ;  but  the  principle  stands 
forever.  DeZeng  has  eliminated  from  his  beau- 
tiful optophorometer  the  binocular  feature,  the 
only  thing  that  ever  marred  his  instrument.  In 
its  perfected  state  it  is  a  monocular  phorometer 
and  a  cyclophorometer  in  combination.  Its 
beauty  and  utility  are  beyond  criticism,  and,  at 
the  risk  of  damaging  it,  I  have  brought  it  with 
me  to  show  it.  It  is  more  beautiful  than  mine, 
more  convenient  of   use,   and  just  as  accurate. 


52  Routine  in  Bye  Work 

With  the  DeZeng  instrument  all  the  tests  of  the 
two  eyes,  taken  separately,  can  be  made  in  six  to 
ten  minutes,  including  the  record  of  the  findings. 
It  will  quickly  drive  all  binocular  phorometers 
from  the  field. 

Having  said  this  much  about  the  monocular 
phorometer,  we  can  now  take  up  the  routine  of 
its  use.  The  test  object  should  be  a  small  point 
of  light,  though  it  may  be  the  blaze  of  an  ordi- 
nary candle.  It  should  be  distant  from  the  pa- 
tient twenty  feet — practical  infinity.  .  The  pupil 
must  not  be  under  the  influence  of  either  a  mydri- 
atic or  a  myotic,  but  the  two  eyes  should  be  as 
set  forth  in  the  routine  test  for  determining  the 
presence  or  absence  of  focal  errors,  and,  if  pres- 
ent, their  character.  The  uninfluenced  pupils 
and  ciliary  muscles,  throughout  the  preliminary 
test,  are  implied  in  the  expression :  "  The  rou- 
tine worker  now  turns  from  the  trial  case  to  the 
phorometer." 

With  the  DeZeng  monocular  phorometer 
turned  into  position,  as  if  the  optometer  part  was 
to  be  used,  but  with  its  cells  empty,  the  spirit 
level  should  be  regulated  and  one  eye  or  the 
other  chosen  for  the  testing  of  the  tonicity  of  the 
four  recti  muscles  in  the  four  cardinal  directions 
only.  Take  the  right  eye,  since  in  making  rec- 
ords  "  O.    D."   is   always   written   first.      There 


Routine  in  Eye  Work  53 

should  be  nothing  but  empty  space  in  front  of 
the  left  eye,  and  this,  throughout  the  test  of  the 
right  eye,  should  be  the  fixing  eye.  The  ten- 
degree  prism  should  be  turned  into  position,  base 
in,  before  the  right  eye,  which  will  throw  the 
retinal  image  nasalward,  outside  the  fusion  area. 
The  false  object  will  be  thrown  directly  to  the 
right,  and  it  should  be  perfectly  level  with  the 
true  or  fixed  object.  If  not  level,,  it  is  because 
muscle  tonicity  has  turned  the  eye  either  up  or 
down,  the  false  object  having  gone  in  the  oppo- 
site direction.  Want  of  levelness  demands  that 
the  rotary  prism  should  be  turned  into  position, 
the  rotary  screw  directly  out,  and  the  index  of 
prism  at  zero.  The  prism  is  now  so  rotated  as 
to  bring  the  false  object  level  with  the  true  or 
fixed  object.  The  extent  of  this  rotation  is 
noted;  and  if  the  false  object  had  to  be  elevated, 
the  note  would  read  R.  hyperphoria  "  so  many  " 
degrees;  but  if  the  false  object  had  to  be  de- 
pressed, the  reading  would  be  R.  cataphoria  "  so 
many  "  degrees.  Either  now,  or  as  well  at  the 
end  of  the  tonicity  tests  of  the  recti  muscles,  the 
proof  test  for  hyperphoria  should  be  applied. 
It  consists  of  a  Maddox  double  prism,  3  to  5 
degrees  each,  to  be  held,  base  line  horizontal, 
first  before  one  eye  and  then  before  the  other, 
allowing  the  patient  to  look  through  only  one  of 


54  Routine  in  Eye  Work 

the  prisms  at  a  time.  Raising  and  lowering  the 
prisms,  the  patient  is  asked  to  name  the  position 
which  makes  the  false  object  nearer  the  true. 
If  there  is  right  hyperphoria,  the  false  object 
will  fuse  with  the  true  or  be  near  it  through  the 
upper  prism,  but  far  removed  when  seen  through 
the  lower  prism  by  the  right  eye.  The  reverse 
will  be  true  when  the  double  prism  is  moved  up 
and  down  before  the  cataphoric  eye.  If  the  false 
and  true  objects  are  practically  the  same  distance 
apart,  as  the  double  prism  is  raised  and  low- 
ered before  each  eye,  there  is  no  vertical  imbal- 
ance. 

The  ten-degree  prism  must  now  be  turned  out 
of  the  way,  and  the  six-degree  prism,  base  up, 
should  be  turned  into  position.  The  rotary  prism 
is  now  turned  so  that  the  screw  is  directly  up 
and  the  index  at  zero.  The  retinal  image  for 
this  eye  is  now  displaced  directly  above,  beyond 
the  fusion  area,  so  that  the  false  object  would 
appear  below,  and  should  be  directly  below  the 
true  or  fixed  object.  If  directly  in  line,  there  is 
lateral  orthophoria  for  distance ;  but  if  not  verti- 
cally beneath,  the  rotary  prism  must  be  made  to 
move  it  into  that  position.  The  index  will  mark 
the  extent  of  the  rotation.  If  the  false  object 
had  to  be  moved  from  the  left,  the  record  would 
read  R.  exophoria  "  so  many  "  degrees ;  but  if  it 


Routine  in  Eye  Work  55 

had   to  be  moved   from   the   right,   the   reading 
would  be  R.  esophoria  "  so  many  "  degrees. 

Again  revolving  the  rotary  prism  into  neutral- 
ity, the  convergence  test,  by  means  of  a  dot  with- 
out lines,  must  be  made.  The  false  dot  standing 
directly  under  the  true  would  show  lateral  ortho- 
phoria in  the  near,  for  the  card  on  which  is  the 
dot  should  be  held  at  the  reading  distance,  with 
the  dot  in  the  horizontal  plane  with  the  eyes. 
Should  the  false  dot  not  be  in  the  vertical  plane 
with  the  true  dot,  the  rotary  prism  should  be 
made  to  move  it  into  that  plane.  If  it  had  to  be 
brought  from  the  left,  the  reading  should  be  R. 
exophoria  "  so  many  "  degrees  in  the  near ;  but 
if  from  the  right,  it  should  be  recorded  R.  eso- 
phoria "  so  many  "  degrees  in  the  near.  Since 
this  is  the  convergence  test  and  both  interni  have 
received  the  same  impulse  from  the  convergence 
center,  the  record  could  leave  out  "  R.,"  if  it  be 
the  right  eye  under  test — that  is,  if  the  false  im- 
age belongs  to  the  right  eye ;  and  the  same  should 
be  done  in  the  near  test  of  the  left  eye.  In  either 
case  want  of  convergence  power  would  be  re- 
corded, "  Exophoria  in  the  near ;  "  and  excess 
of  convergence  would  be  recorded,  "  Esophoria 
in  the  near."  The  far  and  the  near  tests  always 
correspond  when  the  ciliary  muscles  have  normal 
tonicity;  they  are  always  out  of  harmony  when 
the   ciliary   muscles   are   wanting   in   tonicity   or 


56  Routine  in  Eye  Work 

when  they  have  excessive  tonicity.  The  right 
eye  having  been  tested,  the  left  may  be  tested  in 
the  same  manner  and  proper  records  made. 

The  recti  muscles  of  both  eyes  having  been 
tested  as  above  set  forth,  the  next  step  in  the 
routine  use  of  the  phorometer  should  be  to  deter- 
mine the  presence  or  absence  of  cyclophoria,  and, 
if  present,  whether  plus  or  minus.  To  do  this, 
the  rods  on  both  sides  must  be  placed  in  front 
of  their  respective  eyes,  with  the  axes  of  the 
rods  vertical,  so  that  the  streak  of  light  may  be 
horizontal  for  each  eye  alone.  The  six-degree 
prism,  base  up,  must  be  placed  in  position  be- 
fore one  eye,  so  as  to  throw  the  retinal  image 
of  that  streak  entirely  above  the  fusion  area,  the 
streak  itself  being  below.  If  the  two  streaks  are 
parallel,  the  obliques  have  normal  tonicity.  If 
these  streaks  diverge  on  the  side  opposite  the 
prism,  there  is  plus  cyclophoria ;  but  if  they  di- 
verge on  the  side  corresponding  to  the  prism, 
there  is  minus  cyclophoria.  In  either  case  the 
rod  in  front  of  the  prisms  should  be  so  revolved 
as  to  make  the  two  streaks  parallel.  The  index 
will  name  the  amount  of  the  error,  and  the  direc- 
tion of  its  rotation  will  name  the  kind  of  error. 
The  eye  behind  the  displacing  prism  is  the  one 
under  test.  The  one  eye  having  been  tested,  its 
displacing  prism  should  be  turned  out  of  the  way, 


Routine  in  Eye  Work  57 

and  the  six-degree  prism  belonging  to  the  other 
side  should  be  placed  for  testing  it.  Usually 
when  one  eye  shows  plus  cyclophoria,  the  other 
will  show  the  same ;  and  since  this  is  the  case, 
the  record  would  read  plus  (or  minus)  cyclo- 
phoria "  so  many  "  degrees,  leaving  out  the  let- 
ters "  R  "  and  "  L." 

Immediately  following  the  tonicity  tests  of  the 
twelve  ocular  muscles  and  the  taking  of  the  con- 
vergence power  of  the  interni,  the  duction  power 
of  each  individual  muscle  should  be  ascertained. 
The  routine  order  should  be :  First,  superduc- 
tion ;  second,  subduction ;  third,  abduction ; 
fourth,  adduction;  fifth,  minus  cycloduction ; 
sixth,  plus  cycloduction.  In  taking  the  duction 
power  of  the  recti  muscles,  the  rotary  prism 
alone  is  necessary,  and  this  before  one  eye  only. 
The  test  object  should  be  a  point  of  light  or  even 
a  candle  blaze.  This  testing  of  the  recti  muscles 
should  be  in  the  four  cardinal  directions  only. 
For  the  vertical  ductions  the  screw  of  the  rotary 
prism  must  be  horizontal  and  the  index  of  prism 
must  be  at  zero.  Rotating  the  apex  of  the  prism 
up,  the  retinal  image  of  the  test  object  is  being 
moved  downward.  The  superior  rectus  makes 
the  macula  keep  pace  with  the  moving  image  to 
the  extent  of  its  power,  thus  preventing  diplopia. 
The  point  reached  by  the  index  at  the  moment 


58  Routine  in  Eye  Work 

diplopia  occurs  is  the  measure  of  superduction, 
which  should  be  noted  as  "  so  many  "  degrees 
R.  (or  left)  superduction.  Returning  the  index 
to  zero,  the  apex  should  now  be  rotated  down, 
which  carries  the  retinal  image  upward,  the  in- 
ferior rectus  compelling  the  macula  to  keep  pace 
with  the  moving  image  so  long  as  possible,  thus 
preventing  diplopia.  At  the  moment  of  diplopia 
the  index  points  to  the  degree  mark  of  subduc- 
tion,  to  be  noted  as  "  so  many  "  degrees  of  R.  (or 
L.)  subduction. 

Moving  the  screw  into  the  vertical  position 
and  placing  the  index  at  zero,  the  phorometer  is 
ready  for  taking  horizontal  duction,  both  right 
and  left.  Rotating  the  prism  apex  out,  the  reti- 
nal image  in  that  eye  is  made  to  move  directly 
nasalward,  while  the  external  rectus  is  compell- 
ing the  macula  to  keep  pace  with  the  moving 
image  in  the  interest  of  binocular  single  vision. 
At  the  moment  of  diplopia  the  index  points  to 
the  degree  of  abduction  for  that  eye,  and  the  note 
should  be  made  "  so  many  "  degrees  of  R.  (or 
L.)  abduction.  Returning  the  index  to  zero,  the 
apex  of  the  prism  should  now  be  rotated  nasal- 
ward.  This  will  cause  the  retinal  image  to  move 
directly  outward,  but  the  internal  rectus  will 
make  the  macula  keep  pace  with  the  moving 
image  to  the  extent  of  its  power,  and  up  to  this 


Routine  in  Eye  Work  59 

limit  there  will  be  binocular  single  vision.  When 
the  rotation  passes  the  limit  of  power,  diplopia 
at  once  manifests  itself.  The  index  will  then 
stand  at  the  point  marking  the  extent  of  the  ro- 
tation of  the  eye,  which  should  be  noted  as  "  so 
many  "  degrees  of  R.  (or  L.)  adduction. 

The  duction  power  of  all  the  recti  of  one  eye 
having  been  taken,  the  rotary  prism  for  that  eye 
should  be  turned  out  of  the  way,  and  that  for 
the  other  eye  should  be  placed  ready  for  action. 
Precisely  the  same  steps  should  be  repeated  in 
determining  the  duction  power  of  its  four  recti. 
The  same  records  should  be  noted  as  in  connec- 
tion with  the  tests  of  the  muscles  of  the  other 
eye.  The  results  of  these  tests  must  be  com- 
pared with  what  is  known  to  be  the  normal  duc- 
tion power  of  these  several  muscles. 

In  taking  cycloduction,  the  rods  only  must 
stand  before  the  two  eyes,  and  their  axes  must 
be  vertical.  The  rods  should  be  the  same  color 
on  each  side,  for  otherwise  the  fusion  effort  on 
the  part  of  the  obliques  would  fall  short  of  the 
normal  to  them.  Only  one  rod  should  be  rotated 
at  a  time.  Rotating  the  axis  out  tests  the  power 
of  the  inferior  oblique  of  that  eye.  The  instant 
that  the  streak  of  light  doubles,  the  rotation 
should  cease.  The  index  now  points  to  the  de- 
gree mark  on  the  scale,  showing  the  extent  of 


60  Routine  in  Eye  Work 

the  wheel-like  motion  effected  by  the  inferior 
oblique  of  that  eye,  and  should  be  noted  "  so 
many  "  degrees  of  R.  (or  L.)  plus  cycloduction. 
The  axis  of  the  rod  having  been  returned  to  zero 
for  a  moment's  rest,  it  should  now  be  rotated 
toward  the  nose  up  to  the  point  of  doubling  the 
streak.  The  index  at  this  point  indicates  the  ex- 
tent of  the  wheel-like  rotation  effected  by  the 
superior  oblique  of  that  eye,  and  it  should  be 
noted  as  "so  many  "  degrees  of  R.  (or  L.)  minus 
cycloduction. 

The  cycloduction  of  the  one  eye  having  been 
taken,  the  rod  before  it  should  be  set  in  the  verti- 
cal, and  the  rod  before  the  other  eye  should  be 
rotated  first  out,  for  determining  its  plus  cyclo- 
duction, and  then  in,  for  showing  the  minus 
cycloduction.  These  cycloductions  should  be 
compared  with  what  is  known  to  be  normal. 

It  should  be  clearly  understood  that  cardinal 
ductions  are  measured  in  "  degrees  of  prism," 
while  cycloductions  are  measured  in  "  degrees  of 
arc. 

If  the  tonicity  tests  and  the  duction  measure- 
ments are  so  nearly  normal  that  no  operation 
would  be  indicated,  the  preliminary  examination 
may  end  here. 

The  tonicity  tests  having  shown  a  high  degree 
of  heterophoria,  routine  would  call  for  the  plac- 


Routine  in  Eye  Work  61 

ing  of  a  deep-red  glass  before  one  eye.  Should 
this  cause  diplopia,  the  case  is  clearly  one  for 
operation.  The  cardinal  versions  should  now  be 
taken,  either  by  means  of  the  tropometer  or  the 
perimeter.  Oblique  versions  need  never  be  taken. 
The  cardinal  versions  should  be  noted — up, 
down,  right,  left.  "  Superversion,"  "  subver- 
sion," "  abversion,"  and  "  adversion  "  are  all 
good  terms  and  in  harmony  with  other  nomen- 
clature. In  order  to  reach  a  correct  conclusion 
as  to  what  muscle  should  be  operated  upon  in  a 
given  case  of  heterophoria,  and  whether  the  op- 
eration should  be  a  partial  tenotomy  of  the 
stronger  muscle  or  a  shortening  of  the  weaker 
muscle,  one  or  both,  the  tonicity,  duction,  and 
version  tests  must  all  be  compounded,  and  each 
test  must  be  given  its  proper  value. 

If  a  given  case  is  one  of  heterotropia,  the  to- 
nicity and  version  tests  only  are  possible.  Duction 
is  out  of  the  question,  because  of  the  absence  of 
binocular  single  vision.  Vision  in  one  eye  may 
be  so  low  as  to  make  the  tonicity  tests  very  dif- 
ficult, if  not  impossible ;  but  they  should  be  at- 
tempted in  every  case.  In  this  a  red  glass  in 
front  of  the  dull  eye  will  be  helpful.  Version 
tests  are  not  so  important  in  cases  of  heterotro- 
pia as  in  cases  of  heterophoria. 

The  most  important  step  in  the  study  of  any 


62     ,  Routine  m  Bye  Work 

case  of  heterotropia,  unless  one  of  the  eyes  is 
mentally  blind,  is  the  fusion  test.  If  the  two 
images  cannot  be  brought  together  by  the  rotary 
prism,  binocular  single  vision  can  never  be  es- 
tablished by  any  operative  procedure.  This  is  es- 
pecially true  of  squinting  eyes,  with  vision  about 
as  good  in  one  eye  as  in  the  other — cases  of  an- 
tipathy to  binocular  single  vision. 

When  one  eye  is  totally  blind  or  absent,  the 
preliminary  test  is  a  very  short  one  and  consists 
in  first  placing  a  +2.00  sphere  before  the  seeing 
eye  and  thus  determine  if  it  is  hyperopic,  or  a 
— 1.00  or  — 2.00  to  determine  if  it  is  myopic,  and 
next  hold  a  +.50  cylinder,  axis  first  vertical  and 
then  horizontal,  to  determine  the  absence  or  pres- 
ence of  astigmatism. 

Now  the  patient  is  ready  to  be  sent  into  the 
waiting  room  to  be  prepared  for  the  final  exam- 
ination. The  routine  use  of  homatropine,  gr. 
viii  to  distilled  water  one  fluid  ounce,  for  putting 
at  rest  the  ciliary  muscles,  is  the  most  satisfac- 
tory agent,  both  to  the  patient  and  to  the  practi- 
tioner. One  drop  in  each  eye  every  three  to  five 
minutes  until  ten  drops  have  been  instilled  into 
each  eye  should  be  the  rule  in  all  patients  under 
forty-five  years  of  age.  From  the  age  of  forty- 
five  to  forty-eight,  five  to  seven  drops  would  be 
sufficient.     Beyond  forty-eight,  one  drop  should 


Routine  in  Eye  Work  63 

be  put  in  each  eye.  Patients  will  often  plead 
that  "  drops "  be  not  used,  not  understanding 
the  "  why  and  wherefore."  If  the  explanation  is 
not  accepted,  declination  to  further  investigate 
should  be  made.  They  will  say,  sometimes,  that 
opticians  claim  that  "  drops  "  are  not  necessary, 
but  even  harmful.  This  should  be  met  by  the 
statement :  "Any  work  done  without  the  drops 
is  guesswork,  and  this  I  cannot  afford  to  do.  I 
cannot  do  the  further  work  unless  you  submit 
to  the  use  of  the  drops,  nor  can  anybody  else  do 
it  as  it  should  be  done  without  them.  They  are 
not  harmful."  The  necessity  for  enforced  rest 
of  the  ciliary  muscles  in  those  under  forty-eight 
years  should  be  made  clear,  and  the  importance 
of  detecting  disease  processes  in  the  older  should 
be  emphasized,  a  wide-open  pupil  being  essential 
for  this.     Rarely  will  one  refuse  to  submit. 

The  routine  of  drops  having  been  completed, 
the  patient  is  ready  to  be  returned  to  the  consul- 
tation room  for  the  final  examination.  While 
the  ophthalmometer  might  have  been  used  as  a 
part  of  the  preliminary  examination,  since  its 
findings  are  not  altered  by  the  mydriatic,  it  seems 
better  to  use  it  immediately  before  resorting  to 
the  trial  lenses.  The  value  of  the  ophthalmom- 
eter is  now  universally  conceded,  which  consists 
in  locating  the  axis  of  the  astigmatism  and  in 


64  Routine  in  Eye  Work 

showing  the  quantity  usually  within  .50  D.  The 
skillful  use  of  trial  cylinders  a  little  later  will 
show  if  lenticular  astigmatism  is  a  complication. 
The  ophthalmometer  findings  should  be  noted  as 
made.  Retinoscopy  in  children  and  in  the  un- 
lettered is  essential,  and  is  of  value  in  all  cases. 

While  the  room  is  darkened,  other  patients  in 
process  of  preparation  by  the  mydriatic,  in  what- 
ever stage,  should  be  brought  in  and  measured 
with  the  ophthalmometer  and  then  returned  to 
the  waiting  room,  to  be  recalled  in  the  same  or- 
der later. 

Now  the  trial  case  must  be  appealed  to  as  a 
finality  in  order  that  proper  lenses  may  be  or- 
dered. With  the  trial  frames  properly  placed, 
the  opaque  disc  should  be  placed  before  the  right 
eye.  The  letters  called  with  the  left  eye  shows 
the  unaided  acuteness  of  vision  for  that  eye.  If 
worse  than  the  vision  shown  in  the  preliminary 
test,  the  appeal  must  be  made  to  the  plus  lenses ; 
if  no  worse  than  the  vision  shown  in  the  prelimi- 
nary test,  minus  lenses,  spherical  and  cylindrical, 
must  be  resorted  to. 

I  would  have  you  view  the  test  case  for  a  mo- 
ment as  to  the  arrangement  of  the  lenses.  The 
cylinders  all  have  their  handles  at  35  degrees  to 
the  axis,  those  in  one  row  being  to  the  right  of 
the  axis  and  those  in  the  other  row  to  the  left  of 


Routine  in  Eye  H'ork  65 

the  axis.  The  former  should  all  be  in  the  right- 
hand  row,  and  the  latter  all  in  the  left-hand  row. 
For  this  arrangement  of  handles  we  are  indebted 
to  A.  E.  Prince.  The  convex  cylinders  in  the 
right  row  should  be  used  in  testing  the  left  eye, 
and  those  in  the  left  row  for  testing  the  right 
eye  in  astigmatism  according  to  the  rule.  When 
these  cylinders  are  thus  placed,  with  axes  at  90 
degrees,  the  handles  will  be  up  and  out  35  de- 
grees. The  concave  cylinders  in  the  right  row 
should  be  used  for  the  right  eye,  and  those  in  the 
left  row  for  the  left ;  for  thus  used,  when  their 
axes  are  at  180  degrees,  the  handles  will  be  up 
and  out  35  degrees.  In  astigmatism  against  the 
rule  the  order  of  use  would  be  reversed.  The 
full  diopter  spheres  and  cylinders  in  all  the  right- 
hand  rows  should  have  their  handles  turned  to 
the  left,  which  adds  greatly  to  the  convenience 
of  handling  both  the  full  and  fractional  lenses. 

Hyperopia  being  suspected,  in  the  front  cell 
should  be  placed  the  plus  cylinder  indicated  by 
the  ophthalmometer,  less  .50  D,  with  its  axis  in 
the  position  located  by  it.  In  the  back  cell  should 
be  placed,  by  guess,  the  plus  sphere  indicated 
by  the  acuteness  of  vision  through  the  cylinder 
only.  Now  with  a  +.50  D  in  the  left  hand  and  a 
— .50  D  in  the  right  hand,  they  should  be  held 
alternately  in  front  of  the  combination  already 
5 


66  Routine  in  Eye  Work 

in  the  frame  for  determining  if  the  first  sphere 
must  be  increased  in  strength  or  must  be  made 
weaker.  Thus  proceeding,  it  is  not  long  until  the 
sphere  of  proper  strength  has  been  found.  By 
means  of  either  a  +.50  cylinder  or  a  — .50 
cylinder  it  may  be  shown  quickly  if  the  original 
cylinder  is  of  proper  strength  or  must  be  made 
stronger  or  weaker,  and  by  use  of  the  two  it 
may  be  shown  if  the  sphere  must  remain  the 
same  as  already  shown  or  be  changed  in  har- 
mony with  a  change  in  the  strength  of  the  cylin- 
der. 

The  left  eye  having  been  thus  tested,  the 
opaque  disc  should  be  placed  before  it  in  the 
extra  cell  in  front  of  the  cylinder,  and  the  test 
of  the  right  eye  should  be  accomplished  in  the 
manner  outlined  in  the  correction  of  the  left  eye. 

The  combinations  determined  by  the  trial 
lenses  and  the  acuteness  of  vision  obtained  should 
be  recorded.  The  pupillary  distance  and  the 
bridge  measurement  must  be  accurately  taken 
and  recorded.  If  the  patient  is  forty-five  or 
older,  the  presbyopia  for  the  given  age  must  be 
entered.  These  things  are  all  to  be  done  without 
consulting  the  will  of  the  patient ;  but  in  the 
choice  of  frames,  both  as  to  character  and  qual- 
ity, the  patient's  desire  must  be  gratified. 

When  ready  to  write  the  order  for  the  glasses, 


Routine  in  Eye  Work  67 

the  record  as  a  whole  must  be  studied.  Should 
two  cases  be  exactly  alike  as  to  spherical  correc- 
tion, but  different  as  to  adjustment  of  the  lateral 
muscles,  one  esophoric  and  the  other  exophoric, 
the  plus  correction  for  the  former  should  be  full, 
but  for  the  latter  a  deduction  should  be  made 
from  the  plus  correction.  The  reverse  would  be 
true  of  the  same  two  cases  if  minus  sphericals 
stood  in  the  record  and  the  lenses  are  intended 
for  near  use.  A  full  minus  correction  is  always 
proper  for  distant  wear.  In  making  the  order, 
the  strength  of  the  astigmatic  correction  should 
be  accurately  copied  in  all  cases.  If  there  is  a 
hyperphoria  of  quantity  too  slight  to  demand  op- 
eration, the  lens  for  the  hyperphoric  eye  should 
be  ground  on  a  prism  of  proper  strength,  base 
down.  The  lens  for  the  cataphoric  eye  should 
not  be  prismatic.  Esophoria  and  exophoria,  not 
requiring  operation,  should  be  helped  by  mak- 
ing both  lenses  prismatic  to  an  equal  extent,  the 
bases  for  the  former  being  out  and  for  the  lat- 
ter being  in.  This  could  be  done  by  adding  to  or 
taking  from  the  pupillary  measurement,  by  de- 
centering  the  lenses  in  or  out,  or  by  having  each 
ground  on  a  proper  prism.  While  the  record 
should  be  copied  as  to  the  strength  of  required 
cylinders,  a  complicating  cyclophoria  would  jus- 
tify a  slight  change  of  axes.     If  there  is  plus 


68  Routine  in  /:\v  Work 

cyclophoria  and  the  record  shows  plus  cylinders 
converging,  they  should  be  ordered  less  converg- 
ing; but  if  diverging,  the  order  should  call  for 
greater  divergence.  The  variation,  however, 
should  rarely  be  more  than  5  degrees  for  each 
cylinder.  In  cases  of  astigmatism  against  the 
rule,  in  changing  the  axes  of  plus  cylinders,  the 
reverse  of  the  rule  given  above,  known  as  the 
N.  C.  Steele  rule,  should  be  observed.  In  either 
case,  should  the  cylinders  be  minus,  the  reverse 
of  all  said  above  about  plus  cylinders  would  be 
the  order. 

The  patient  should  be  told  that  high  degrees 
of  a  muscle  error,  or  any  combination  of  muscle 
errors,  demand  operations.  A  moderate  want  of 
tonicity  of  the  recti  muscles  may  be  remedied  by 
rhythmic  prismatic  exercise,  while  such  a  condi- 
tion of  the  obliques  may  be  cured  by  the  same 
character  of  exercise  by  means  of  weak  plus  or 
minus  cylinders  so  placed  as  to  call  into  action 
the  weak  obliques.  Deficient  convergence  power 
should  be  treated  by  candle  exercise — moved 
from  arm's  length  to  a  point  seven  inches  from 
the  eyes,  also  rhythmic  in  character.  Want  of 
ciliary  power  should  be  remedied  by  exercise 
with  weak  minus  spherical  lenses. 

There  are  some  important  points  about  bifo- 
cals which  should  be  routinely  observed  in  mak- 


Routine  in  Eye  Work  69 

ing  the  order.  Bifocals  should  never  be  given 
if  there  is  much  difference  in  the  spherical  re- 
fraction of  the  two  eyes,  for  such  patients  must 
learn  to  look  through  the  lens  centers  both  in 
far  and  near  seeing.  Perfection  bifocals  and  the 
Franklin  divided  lenses  have  the  advantage  over 
all  others  in  that  the  cutting  can  be  done,  and 
should  be  done,  so  that  the  centers  of  the  upper 
and  lower  parts  may  coincide.  In  these  combi- 
nations the  eyes  glide  from  one  part  to  the  other. 
In  the  fused  and  cemented  bifocals  the  centers 
of  the  upper  and  lower  parts  cannot  coincide ; 
hence  in  passing  from  one  to  the  other  the  eyes 
must  jump.  In  any  form  of  bifocals  the  centers 
of  the  reading  lenses  must  be  on  the  same  hori- 
zontal line;  otherwise  comfortable  near  work 
through  them  cannot  be  done. 

After  lenses  have  been  finished,  they  should 
always  be  inspected ;  and  if  any  error  has  been 
made  in  grinding  or  cutting,  it  should  be  cor- 
rected. One  of  the  most  important  things  in 
the  inspection  is  the  proper  centering  of  lenses, 
whether  for  distant  or  near  use ;  and  especially 
is  this  important  as  to  the  reading  part  of  bifo- 
cals of  whatever  kind. 

One  of  the  most  important  things  in  the  whole 
routine  of  eye  work  is  the  delivery  of  the  lenses 
to  the  patient,  which  should  never  be  done  with- 


70  Routine  in  Eye  Work 

out  explicit  instructions  on  two  points:  (1)  A 
straight  edge  should  always  pass  through  the 
four  joints  of  spectacles,  or  should  coincide  with 
the  long  axes  of  the  eyeglasses;  (2)  whether  the 
lenses  are  in  spectacle  frames  or  eyeglass  trap- 
pings, they  must  always  be  level  in  front  of  the 
eyes  and  equally  distant  from  them ;  and  if  in- 
clined at  all,  this  should  be  slightly  out  at  the  top. 

Many  a  complaint  comes  to  an  oculist  either 
because  these  points  have  not  been  impressed  or 
because  they  have  not  been  observed.  If  a  pa- 
tient should  ask  for  a  guarantee  (which  should 
never  be  granted),  the  above  rules  should  be 
doubly  or  trebly  impressed. 

There  is  nothing  simple  about  the  work  of  cor- 
recting visual  defects  and  muscular  deficiencies, 
and  it  should  be  unlawful  for  any  one  to  engage 
in  this  practice  who  is  not  educated  medically 
and  scientifically. 


Mydriatic  No  Mydriatic 

c  o  o 

O  3  p 

a"  »  c  2.  S.  o'  SL 

^  2.  ^  o  o  sr 

o  ?•  SL  3  3  J  _  . 

T3 

3  --^^ 

'  *         f-"       3D  * 

r    50  •       P1    m 

w    b    P    P     <    < 

3=       II       II 
•a 

■i 

'-,      1  cL     cL      S-     3- 

:  1-     o      o 

ST      nT 

3         3 


CO 

c 

CO 

CO 

X 

c 

"0 

c 
•a 

T3 

•i 

rt 

« 

< 

►1 

^ 

*0 

n 

Q- 

a- 

p- 

c 
o 

c 
o 

o 

1 

O 

3 

5' 

3 

5' 

3 

(B 

<    < 


CO  c         c       W       CO         » 


0     0 


0) 
T3 

3" 
O 


ty  cr  c  c       oj 

<  <  tr  tr     t) 

f»  r»  a-  cl.      p- 

|.  2-  §  g        g. 

o  o  n-.  c.      5>      ^       a-     s- 

co         co       3  3  o  o' 

n       n  3  3  _(_     J_ 

•o      "0 


> 


<3      £  „  -°     -°      °     2      *» 

p  "  *  *-r  r  -  £  i  i  f  .f 


3       ° 

3  3 


C  C  ~  o 

o  o 

o'  o' 

3  3 


2  3  g  *  ^  ^ 

»P  O  3-3-3-3- 

>  >       -°         -°  ++++        > 

<  <         CL        CL  ^    ^-"  ^2?  *-"  *-"       CL 

^         »        DL        Ou      -°    °-.0~°   0©00       =T 

co  3         c  C  m  PT1       <">    O    O    <->         2 

3         3        S-'     S'         O  O        '     •     •     ' 

*0  T3        B    3>    9    cp 


O  O 

3  3 


a-      sr     x  x  x  x 
o       o      •    •    •    • 

5'      5>* 


<<  v;       cu    **   £ 

CL  CL 

C  C 

o  o 


O         O 
3         3 


o    o    o    c 

■-  1  I 

+  1+5    1 

r  r 


+  i  + 


$4.00       OPHTHALMIC  MYOLOGY       $4.00 
Second  Edition. 

The  first  chapter,  on  "  Fundamental  Princi- 
ples," has  been  enlarged  from  54  to  145  pages, 
and  has  been  illuminated  by  23  additional  cuts. 

A  study  of  the  Ocular  Muscles  from  the  mus- 
cle side  of  the  questions,  including  the  physics  of 
ocular  adjustments  and  motions.  This  book  and 
its  companion  volume,  "  Ophthalmic  Neuro- 
Mvology,"  are -the  only  books,  on  the  eye  mus- 
cles, in  any  language,  based  on  the  correct  fun- 
damental principles,  as  set  forth  in  Chapter  1. 

Of  these  principles,  Black,  in  Colorado  Medicine,  says:  "The 
author  is  right.  He  has  literally  knocked  Helmholtz's  theory 
into  a   cocked   hat." 

Wiener,  in  Annals  of  Ophthalmology,  says:  "The  points 
at  issue  so  logically  and  concisely  depicted  on  pages  32  to  34  are 
unanswerable.  An  ophthalmologist  not  taking  the  opportunity 
of  studying  this  volume  is  doing  himself  an   injustice." 

Menacho,  in  Archivas  de  Oftalmologia,  Barcelona,  says: 
"It  is  a  profound  work,  and  we  hope  soon  to  see  it  appear  in  a 
Spanish  translation  for  the  diffusion  of  such  useful  knowledge 
among   our  people." 

London  Lancet:  "It  is  well  worthy  of  the  consideration  of 
the   learned   in   these   matters." 

Wurdemann,  in  Ophthalmology,  says:  "Thorough  study  of 
the  author's  reasonings  leads  a  student  to  an  acceptance  of  his 
propositions  and  their  application   in  practical   work." 

Southern  Medical  Journal :  "  It  seems  to  the  reviewer  that 
the  position  assumed  in  the  first  chapter  is  impregnable  and  the 
statements   unanswerable." 

Dr.  Daniel,  Professor  of  Physics,  Vanderbilt  University, 
says:  "  Having  given  the  subjects  treated  some  attention  in 
friendly  association  with  the  author,  I  am  convinced  that  in 
'  Ophthalmic   Myology  '    Savage   teaches  the   truth." 

Published  by  the  Author,   G.   C.    Savage,   M.D.,   Nashville,  Tenn. 

Printed  by   McQuiddy   Printing   Company,   Nashville,   Tenn. 


$2.50  $2.50 

OPHTHALMIC  NEURO-MYOLOGY 

A  study  of  the  Ocular  Muscles  from  the  brain 
side  of  the  questions.  The  late  Swan.  M.  Bur- 
nett said :  "  I  am  charmed  with  the  clearness  and 
directness  with  which  you  have  put  the  problems 
and  their  solution." 

Hess,  of  Wurzburg,  Germany,  says :  "  I  wish 
to  tell  you  how  excellently  you  have  treated  the 
subject,  and  to  congratulate  you  that  you  have 
succeeded  to  make  clear  these  most  difficult 
questions." 

Snell,  Sheffield,  England,  said :  "  It  seems  to 
me  that  your  views  are  correct." 

Published   by  the  Author,  G.   C.   Savage,   M.D.,   Nashville,  Tenn. 


$10.00  $10.00 

THE  MUSCLE  INDICATOR 

This  device,  shown  on  page  15,  reduced  in 
size  and  otherwise  improved,  is  manufactured 
and  sold  by 

Joseph  C.  Snodgrass, 
167  Fourth  Avenue,  North, 

Nashville,    Tenn. 

It  shows  every  phase  of  every  Ocular  Muscle 
and  every  combination  of  Ocular  Muscles — nor- 
mal, abnormal,  or  pathological.  With  "  Oph- 
thalmic Myology "  and  "  Ophthalmic  Neuro- 
Myology "  as  textbooks,  any  medical  mind, 
aided  by  the  Muscle  Indicator,  may  become  mas- 
ter of  the  muscle  study. 


THE  MONOCULAR  PHOROMETER   AND 
THE  CYCLOPHOROMETER 

are  the  most  reliable  means  for  testing  the 
tonicity  and  the  duction  power  of  all  the  Oc- 
ular Muscles. 

E.  B.  Meyrowitz,  New  York,  and  F.  A. 
Hardy  &  Co.,  Chicago,  manufacture  the  two  de- 
vices separately,  but  both  to  be  used  on  the  same 
stand.  The  two  instruments,  with  one  stand,  can 
be  had  of  either  firm  for  $50.00.  The  DeZeng- 
Standard  Company,  Camden,  N.  J.,  will  soon  be 
manufacturing  The  Monocular  Phorometer  and 
The  Cyclophorometer  in  a  most  convenient  and 
beautiful  combination,  to  be  used  on  a  floor 
stand  or  wall  bracket.  This  instrument  will  be 
much  more  costly,  and  cannot  be  sold  for  less 
than  $100.00,  probably  more. 


The  Keller  book  of  individual  cards  for  office 
use  is  manufactured  by  D.  F.  Keller  &  Co.,  Chi- 
cago, 111.,  621-631  Plymouth  Court,  to  whom  all 
orders  should  be  sent.     They  are  very  valuable. 


The  record  blanks  on  the  last  page  of  the  ad- 
dress, "Routine  in  Eye  Work,"  are  manufac- 
tured and  sold  by  Shields-Farris  Printing  Com- 
pany, Nashville,  Tenn.,  "  143  Sixth  Avenue, 
North.  They  are  in  pads  of  100  and  can  be  had 
for  25  cents  per  pad,  in  lots  of  one  to  four ;  24 
cents,  in  lots  of  five  to  seven  ;  and  23  cents,  in 
lots  of  eight  to  ten. 


QPTo 


14  DAY  USE 

RETURN  TO  DESK  FROM  WHICH  BORROWED 

OPTOMETRY  LIBRARY 

This  book  is  due  on  the  last  date  stamped  below,  or 

on  the  date  to  which  renewed. 

Renewed  books  are  subject  to  immediate  recall. 

LD21 — 32m — 1,'75                              General  Library 
(S3845l)4970                            University  of  California 

Berkeley 

^ 


